Chem help?

[GRAWRG.]

pleaseeee help. got an exam on friday. looked at the practice exam but i couldnt find the answers (were supposed to be in comments). i just spent a good bit of time typing the stuff up sooo. gonna post it here. post answers to some or all of them, please. the practice exam isnt much use if i dont know whether i got the questions right o.o

thanks.

1. In Bohr's atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus:
A) a photon is emitted
B) a chemical bond is formed
C) no change in energy occurs
D) energy is emitted
E) energy is absorbed

2. How many unpaired electrons are there in an atom of iron in its ground state? (atomic number of iron is 26)
A) 0
B) 1
C) 2
D) 3
E) 4

3. Which of the following is an incorrect designation for an atomic orbital?
A) 6g
B) 3d
C) 3p
D) 4g
E) 3s

4. Which of the following is (are) related to the angular momentum quantum number, 1?
A) the energy of the corresponding atomic orbital
B) the orientation of the corresponding atomic orbital(s)
C) the size of the corresponding atomic orbital(s)
D) the spin state of the electron
E) the shape of the corresponding atomic orbital(s)

5. Which of the following statements about quantum theory are correct?
A) no two electrons can have the same four quantum numbers
B) the filling order of electrons into atomic orbitals is random and follow no pattern
C) when filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital
D) the momentum and position of an electron can be determined precisely
E) the wavefunction is a direct measure of the probability of finding an electron in a 3D space

6. Which of the following are correctly paired? (the terms are related to each other)
A) high frequency: low energy
B) principal quantum number: spin of an electron
C) Bohr's atomic model: polyelectronic atoms
D) Spin quantum number: 1/2 and -1/2
E) Fluorine: low electron affinity

7. How many electrons can have the following quantum numbers: n=4, l=3, ml (m sub l)=+-2?
A) 1
B) 2
C) 4
D) 8
E) 10

8. Which of the following energies corresponds to light with the longest wavelength?
A) 3.00 x 10^-20 J
B) 4.12 x 10^-19 J
C) 8.50 x 10^-20 J
D) 9.12 x 10^-19 J
E) 3.20 x 10^-18 J

9. List the following atoms in order of increasing atomic radius: B, Ca, Ge, P, Li
A) Li<B<P<Ge<Ca
B) B<Li<P<Ge<Ca
C) Li<B<Ge<Ca<P
D) Ge<Ca<P<Li<B
E) Ca<Li<Ge<B<P

10. For which of the following transitions does the light emitted have the highest frequency?
A) n=4 to n=3
B) n=5 to n=2
C) n=4 to n=1
D) n=6 to n=4
E) n=2 to n=1

11. Which species has this ground-state electron arrangement: 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10?
A) Ni
B) Ni^2+
C) Zn
D) Zn^2+
E) Cu

12. The maximum number of electrons that can occupy an orbital labeled dxy (d sub xy) is:
A) 1
B) 2
C) 3
D) 4
E) 10

13. In what respect does an atom of magnesium, Mg, differ from a magnesium ion, Mg^2+?
A) the positive charge on the nucleus of the ion is two units greater than the nuclear charge on the atom
B) the ion has two more protons than the atom
C) the ion hash two more planetary electrons than thhe atom
D) the ion has a noble gas electron configuration; the atom does not
E) the ion has two more neutrons than the atom

14. The argon atom is isoelectronic with:
A) Cl
B) N^3-
C) Ca
D) Ti^4+
E) Mg

15. Which of the following emission lines in the hydrogen spectrum occurs at the highest frequency?
A) n=4 to n=3
B) n=7 to n=5
C) n=10 to n=8
D) n=4 to n=2
E) n=3 to n=1

16. A student mixes 100mL of .5M NaOH with 100mL of .5M HCl in a styrofoam cup and observes the temperature change of T1. When she repeats this experiment using 200mL of each solution, she observes a temperature change of T2. If no heat is lost to the surroundings or absorbed by the styrofoam cup, what is the relationship between T1 and T2?
A) T1=2T2
B) T1=T2
C) T1=.5T2
D) T1=4T2
E) T1-3T2

17. The standard enthalpy change for the formation of silver chloride from its elements is ___ than the enthalpy change for the formation of silver bromide. AgCl(s) -127.1 kJ/mol AgBr(s) -100.4 kJ/mol
A) less endothermic
B) more endothermic
C) less exothermic
D) more exothermic

18. A balloon has a volume of 1.20 liters at 24.0 degrees celsius. The balloon is heated to 48.0 degrees celsius. Calculate the new volume of the balloon.
A) 1.20 L
B) 1.30 L
C) 1.70 L
D) 2.10 L
E) 2.40 L

19. The valve between a 5-L tank containing a gas at 9 atm and a 10-L tank containing a gas at 6 atm is opened. Calculate the final pressure in the tanks.
A) 3 atm
B) 4 atm
C) 7 atm
D) 15 atm
E) none of these

20. Gaseous C2H4 reacts with O2 according to the following equation: C2H4(g)+3O2(g)->2CO2(g)+2H2O(g)
What volume of oxygen at STP is needed to react with 1.50 mol of C2H4?
A) 4.50 L
B) 33.6 L
C) 101 L
D) 67.2 L
E) Not enough information is given to solve the problem.

21. A sample of 35.1g of methane gas (CH4) has a volume of 5.20 L at a pressure of 2.70 atm. Calculate the temperature.
A) 78.1 K
B) 46.3 K
C) 275 K
D) 129 K
E) 4.87 K

22. The van der Waals equation, nRT=[P+(n^2a/V^2)](V-nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of these corrections accounts for
A) the possibility of chemical reaction between molecules
B) the finite volume of molecules
C) the quantum behavior of molecules
D) the fact that average kinetic energy is inversely proportional to temperature
E) the possibility of phase changes when the temperature is decreased or the pressure is increased

23. For a particular process q=20 kJ and w=15 kJ. Which of the following statements is true?
A) heat flows from the system to the surroundings
B) the system does work on the surroundings
C) delta E = 35 kJ
D) all of the above are true
E) none of the above are true

24. Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smalest change in temperature?
A) the metal with the higher heat capacity
B) the metal with the lower heat capacity
C) both undergo the same change in temperature
D) you need to know the initial temperatures of the metals

25. A 40.2g sample of a metal is heated to 99.3 degrees celsius and then places in a calorimeter containing 120.0g of water (c=4.18J/g*degreescelsius) at 21.8 degrees celsius. The final temperature of the water is 24.5 degrees celsius. Which metal was used?
A) aluminum (c=.89J/g*degreescelsius)
B) iron (c-.45J/g*degreescelsius)
C) copper (c=.20J/g*degreescelsius)
D) lead (c=.14J/g*degreescelsius)
E) none of these

26. In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. Which of the following is true?
A) the chemical reaction is releasing energy
B) the energy released is equal to s*m*T
C) the chemical reaction is absorbing energy
D) the chemical reaction is exothermic
E) more than one of these

27. C2H5OH(l) + 3O2(g) -> 2CO2(g) + 3H2O(l), deltaH = -1.37 x 10^3 kJ
For the combustion of ethyl alcohol as described in the above equation, which of the following is true?
I. The reaction is exothermic.
II. The enthalpy change would be different if gaseous water were produced.
III. The reaction is not an oxidation-reduction one.
IV. The products of the reaction occupy a larger volume than the reactants.

A) I,II
B) I,II,III
C) I, III, IV
D) III, IV
E) I

28. When .157 mol of a weak base (A^-) is reacted with excess HCl, 6.91 kJ of energy is released as heat. What is deltaH for this reaction per mole of A^- consumed?
A) -22.7 J
B) -1.08 kJ
C) -44.0 kJ
D) +22.7 J
E) +44.0 kJ

29. Using the information below, calculate deltaH for PbO(s).
PbO(s) + CO(g) -> Pb(s) + CO2(g) deltaH= -131.4 kJ
deltaH for CO2(g) = -393.5 kJ/mol
deltaH for CO(g) = -110.5 kJ/mol

A) -151.6 kJ/mol
B) -283.0 kJ/mol
C) +283.0 kJ/mol
D) -372.6 kJ/mol
E) +252.1 kJ/mol

30. Which one of the following types of radiation has the shortest wavelenght, the greatest energy, and the highest frequency?
A) ultraviolet radiation
B) infrared radiation
C) visible red light
D) visible blue light

31. Alpha particles beamed at thin metal foil may
A) pass directly through without changing directions
B) be slightly diverted by attraction to electrons
C) be reflected by direct contact with nuclei
D) a and c
E) a, b, and c

32. When a hydrogen electron makes a transition from n=3 to n=1, which of the following statements is true?
I. Energy is emitted
II. Energy is absorbed
III. The electron loses energy
IV. The electron gains energy
V. The electron cannot make this transition

A) I, IV
B) I, III
C) II, III
D) II, IV
E) V

33. Which of the following statements about quantum theory is incorrect?
A) the energy and position of an electron cannot be determined simultaneously
B) lower energy orbitals are filled with electrons before higher energy orbitals
C) when filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital
D) no two electrons can have the same four quantum numbers
E) all of these are correct

34. Which of the following statements is true?
A) the exact location of an electron can be determined if we know its energy
B) an electron in a 2s orbital can have the same n,l, and ml quantum numbers as an electron in a 3s orbital
C) Ni has 2 unpaired electrons in its 3d orbitals
D) in the buildup of atoms, electrons occupy the 4f orbitals before the 6s orbitals
E) only three quantum numbers are needed to uniquely describe an electron

35. How many f orbitals have the value n=3
A) 0
B) 3
C) 5
D) 7
E) 1

[JuliusCaesar]

1. In Bohr's atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus:
A) a photon is emitted
B) a chemical bond is formed
C) no change in energy occurs
D) energy is emitted
E) energy is absorbed

I hate conceptual stuff, but I'm pretty sure it is A, that or D.

2. How many unpaired electrons are there in an atom of iron in its ground state? (atomic number of iron is 26)
A) 0
B) 1
C) 2
D) 3
E) 4

3. Which of the following is an incorrect designation for an atomic orbital?
A) 6g
B) 3d
C) 3p
D) 4g
E) 3s

4. Which of the following is (are) related to the angular momentum quantum number, 1?
A) the energy of the corresponding atomic orbital
B) the orientation of the corresponding atomic orbital(s)
C) the size of the corresponding atomic orbital(s)
D) the spin state of the electron
E) the shape of the corresponding atomic orbital(s)

5. Which of the following statements about quantum theory are correct?
A) no two electrons can have the same four quantum numbers
B) the filling order of electrons into atomic orbitals is random and follow no pattern
C) when filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital
D) the momentum and position of an electron can be determined precisely
E) the wavefunction is a direct measure of the probability of finding an electron in a 3D space

Not sure on E there.

6. Which of the following are correctly paired? (the terms are related to each other)
A) high frequency: low energy
B) principal quantum number: spin of an electron
C) Bohr's atomic model: polyelectronic atoms
D) Spin quantum number: 1/2 and -1/2
E) Fluorine: low electron affinity

7. How many electrons can have the following quantum numbers: n=4, l=3, ml (m sub l)=+-2?
A) 1
B) 2
C) 4
D) 8
E) 10

8. Which of the following energies corresponds to light with the longest wavelength?
A) 3.00 x 10^-20 J
B) 4.12 x 10^-19 J
C) 8.50 x 10^-20 J
D) 9.12 x 10^-19 J
E) 3.20 x 10^-18 J

9. List the following atoms in order of increasing atomic radius: B, Ca, Ge, P, Li
A) Li<B<P<Ge<Ca
B) B<Li<P<Ge<Ca
C) Li<B<Ge<Ca<P
D) Ge<Ca<P<Li<B
E) Ca<Li<Ge<B<P

10. For which of the following transitions does the light emitted have the highest frequency?
A) n=4 to n=3
B) n=5 to n=2
C) n=4 to n=1
D) n=6 to n=4
E) n=2 to n=1

11. Which species has this ground-state electron arrangement: 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10?
A) Ni
B) Ni^2+
C) Zn
D) Zn^2+
E) Cu

12. The maximum number of electrons that can occupy an orbital labeled dxy (d sub xy) is:
A) 1
B) 2
C) 3
D) 4
E) 10

Don't really remember this, I think it is either b or e

13. In what respect does an atom of magnesium, Mg, differ from a magnesium ion, Mg^2+?
A) the positive charge on the nucleus of the ion is two units greater than the nuclear charge on the atom
B) the ion has two more protons than the atom
C) the ion hash two more planetary electrons than thhe atom
D) the ion has a noble gas electron configuration; the atom does not
E) the ion has two more neutrons than the atom

14. The argon atom is isoelectronic with:
A) Cl
B) N^3-
C) Ca
D) Ti^4+
E) Mg

15. Which of the following emission lines in the hydrogen spectrum occurs at the highest frequency?
A) n=4 to n=3
B) n=7 to n=5
C) n=10 to n=8
D) n=4 to n=2
E) n=3 to n=1

16. A student mixes 100mL of .5M NaOH with 100mL of .5M HCl in a styrofoam cup and observes the temperature change of T1. When she repeats this experiment using 200mL of each solution, she observes a temperature change of T2. If no heat is lost to the surroundings or absorbed by the styrofoam cup, what is the relationship between T1 and T2?
A) T1=2T2
B) T1=T2
C) T1=.5T2
D) T1=4T2
E) T1-3T2

17. The standard enthalpy change for the formation of silver chloride from its elements is ___ than the enthalpy change for the formation of silver bromide. AgCl(s) -127.1 kJ/mol AgBr(s) -100.4 kJ/mol
A) less endothermic
B) more endothermic
C) less exothermic
D) more exothermic

18. A balloon has a volume of 1.20 liters at 24.0 degrees celsius. The balloon is heated to 48.0 degrees celsius. Calculate the new volume of the balloon.
A) 1.20 L
B) 1.30 L
C) 1.70 L
D) 2.10 L
E) 2.40 L

19. The valve between a 5-L tank containing a gas at 9 atm and a 10-L tank containing a gas at 6 atm is opened. Calculate the final pressure in the tanks.
A) 3 atm
B) 4 atm
C) 7 atm
D) 15 atm
E) none of these

20. Gaseous C2H4 reacts with O2 according to the following equation: C2H4(g)+3O2(g)->2CO2(g)+2H2O(g)
What volume of oxygen at STP is needed to react with 1.50 mol of C2H4?
A) 4.50 L
B) 33.6 L
C) 101 L
D) 67.2 L
E) Not enough information is given to solve the problem.

21. A sample of 35.1g of methane gas (CH4) has a volume of 5.20 L at a pressure of 2.70 atm. Calculate the temperature.
A) 78.1 K
B) 46.3 K
C) 275 K
D) 129 K
E) 4.87 K

22. The van der Waals equation, nRT=[P+(n^2a/V^2)](V-nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of these corrections accounts for
A) the possibility of chemical reaction between molecules
B) the finite volume of molecules
C) the quantum behavior of molecules
D) the fact that average kinetic energy is inversely proportional to temperature
E) the possibility of phase changes when the temperature is decreased or the pressure is increased

23. For a particular process q=20 kJ and w=15 kJ. Which of the following statements is true?
A) heat flows from the system to the surroundings
B) the system does work on the surroundings
C) delta E = 35 kJ
D) all of the above are true
E) none of the above are true

Not sure on this one

24. Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smalest change in temperature?
A) the metal with the higher heat capacity
B) the metal with the lower heat capacity
C) both undergo the same change in temperature
D) you need to know the initial temperatures of the metals

25. A 40.2g sample of a metal is heated to 99.3 degrees celsius and then places in a calorimeter containing 120.0g of water (c=4.18J/g*degreescelsius) at 21.8 degrees celsius. The final temperature of the water is 24.5 degrees celsius. Which metal was used?
A) aluminum (c=.89J/g*degreescelsius)
B) iron (c-.45J/g*degreescelsius)
C) copper (c=.20J/g*degreescelsius)
D) lead (c=.14J/g*degreescelsius)
E) none of these

40.2(c)(99.3-24.5)=-120(4.18)(21.8-24.5), c=.45 j/gC, Iron

26. In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. Which of the following is true?
A) the chemical reaction is releasing energy
B) the energy released is equal to s*m*T
C) the chemical reaction is absorbing energy
D) the chemical reaction is exothermic
E) more than one of these

27. C2H5OH(l) + 3O2(g) -> 2CO2(g) + 3H2O(l), deltaH = -1.37 x 10^3 kJ
For the combustion of ethyl alcohol as described in the above equation, which of the following is true?
I. The reaction is exothermic.
II. The enthalpy change would be different if gaseous water were produced.
III. The reaction is not an oxidation-reduction one.
IV. The products of the reaction occupy a larger volume than the reactants.

A) I,II
B) I,II,III
C) I, III, IV
D) III, IV
E) I

28. When .157 mol of a weak base (A^-) is reacted with excess HCl, 6.91 kJ of energy is released as heat. What is deltaH for this reaction per mole of A^- consumed?
A) -22.7 J
B) -1.08 kJ
C) -44.0 kJ
D) +22.7 J
E) +44.0 kJ

29. Using the information below, calculate deltaH for PbO(s).
PbO(s) + CO(g) -> Pb(s) + CO2(g) deltaH= -131.4 kJ
deltaH for CO2(g) = -393.5 kJ/mol
deltaH for CO(g) = -110.5 kJ/mol

A) -151.6 kJ/mol
B) -283.0 kJ/mol
C) +283.0 kJ/mol
D) -372.6 kJ/mol
E) +252.1 kJ/mol

30. Which one of the following types of radiation has the shortest wavelenght, the greatest energy, and the highest frequency?
A) ultraviolet radiation
B) infrared radiation
C) visible red light
D) visible blue light

31. Alpha particles beamed at thin metal foil may
A) pass directly through without changing directions
B) be slightly diverted by attraction to electrons
C) be reflected by direct contact with nuclei
D) a and c
E) a, b, and c

32. When a hydrogen electron makes a transition from n=3 to n=1, which of the following statements is true?
I. Energy is emitted
II. Energy is absorbed
III. The electron loses energy
IV. The electron gains energy
V. The electron cannot make this transition

A) I, IV
B) I, III
C) II, III
D) II, IV
E) V

33. Which of the following statements about quantum theory is incorrect?
A) the energy and position of an electron cannot be determined simultaneously
B) lower energy orbitals are filled with electrons before higher energy orbitals
C) when filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital
D) no two electrons can have the same four quantum numbers
E) all of these are correct

34. Which of the following statements is true?
A) the exact location of an electron can be determined if we know its energy
B) an electron in a 2s orbital can have the same n,l, and ml quantum numbers as an electron in a 3s orbital
C) Ni has 2 unpaired electrons in its 3d orbitals
D) in the buildup of atoms, electrons occupy the 4f orbitals before the 6s orbitals
E) only three quantum numbers are needed to uniquely describe an electron

35. How many f orbitals have the value n=3
A) 0
B) 3
C) 5
D) 7
E) 1

Edit: Goddamned bold face was barely visible -.-

[GRAWRG.]

thank you. very very very much.

theres some stuff i'll probably need explained. don't feel pressured to though, since you've already taken the time to give the answers o.o

1. i wasnt sure about that one either... someone on yahoo answers said energy is absorbed by the electron. "In the Bohr model, an electron absorbs energy as it moves to a higher energy level (farther from the nucleus) and emits energy as it moves to a lower energy level (closer to the nucleus)." but i cant make that make sense to me. for an electron to move, it would have to pull away from the nucleus right? which is energy emission? idk

2. this one really confused me. i think i dont really understand what ground state means (ive already look up the definition). i used 26 electrons and got... 6? or 8? unpaired. can you explain why you would use less than 26 electrons if the atomic number of iron is 26?

3. i got the same answer here, but i wanna confirm that i understood it. 6g is the furthest one out? like, spdfg.. and 6g would be the farthest of all of those? so you never get that far?

for 6 and 7 i think i'll need to read over stuff in the book before talking to you... i dont know what n or l or ml stand for, or the rules for each, or how they're related :/

8. i got C for this. longest wavelength = lowest energy, right? and wouldnt -.08 be less than -.03?

9. can you explain this? i just looked up the rules but. i dont get how adding electrons is going to make the radius decrease, like with Li and B.

10. highest frequency = most energy right? i thought the biggest energy jump was from 1-2, and then the rest were minor. so why wouldnt it be C?

11. i guess this goes back to my problem with ground-state stuff. cause i got Ni... since that electron config = 28 electrons.

12. im thinking E? since with electron configurations it's s2p6d10?

15. again, i thought E for this because of the 1-2 jump

17. i thought it would be more exothermic, since it loses 127.1 kJ/mol, whic is like, 27 kJ/mol more than AgBr

18. obviously it doubled based on your answer... but is that what happens? does volume increase with temperature?

19. how do you get this? id do... the 10L tank has twice the effect of the 5L one. so as they equalize, the 9atm makes twice the jump towards 6atm as the 6atm does towards 9atm. so 9atm jumps to 7atm, and 6 goes up one to 7 atm.

20. blehh. 1.5mol C2H4 = 4.5mol O2. then theres a formula i dont remember with volume,pressure, temp and mass. pv=nRT? and fill that stuff in i guess?

i'll go over the rest when i get home. gotta go to calc now o.o

but tyvm for the answers.

[GRAWRG.]

21. PV=nRT
14.04=nRT
6.4=RT
.76978=T ... this seems related to your answer. my values were kinda rounded... so that'd probably get to .781 but idk how to make that 78.1 K

23. yeah i just got really confused with this. but based on what i just read, q and w are relative to the system, not the surroundings. so A and B would be wrong. so i would say the answer is C?

24. i got confused by this too. i wanted to say the same as you but... is temp change linear? i mean, heat capacity aside... is a 0 degree celsius piece of metal exposed to x amount of heat going to change in temp as much as another sample of the same metal at 40 degrees celsius? so what if the two different samples are also two different temperatures, and have VERY similar heat capacities... could the differences in temperature be significant?

i need a nap. i'll look at the rest later o.o

[JuliusCaesar]

1) Sorry I was really tired when I wrote up these responses so my answer here is completely wrong I didn't see the part where it said the electron is moving OUTWARD away from the nucleus. This means the electron is absorbing energy, because it needs to gain extra velocity to move OUTWARD in the orbit against the inward pull of the protons in the nucleus, much like objects orbiting celestial bodies need more velocity to pull outward against the force of gravity, thus being higher in their orbits. Conversely, electrons moving down energy levels would release energy (as they lose angular momentum) and this energy is given off as a photon (don't ask me why because it is beyond me).

2) Sorry, its 4 actually, again I was really tired. I managed to see "ground state" and interpret it as valence. All ground state means is it isnt excited, all the electrons are where they normally are in an uncharged atom of that element.

NOTE: no offense, but from your questions I assume you aren't too familiar with electron orbital filling, and how the electron configuration relates to the periodic table. Included here ->http://i.imgur.com/YHV3q.png<- is a little homemade periodic table/configuration chart. To find the configuration of any atom on that chart, you just follow it from left to right, top to bottom filling as you go. In a nutshell it works like this. on the far left where the alkaloids are is the "s" sublevel, and as they are stacked downwards vertically we have the 1s, 2s, 3s, and so on groupings. That is to say, the left two columns are the s sub level, and each row is an energy level. The center area with the transition metals is the "d" sublevel and begins at the third level (though in the fourth row, the D level is always an energy level lower than the row, the F level is 2 energy levels below the row), the cluster of 6 columns on the right is "p", and the bottom two rows detactched from the table are the "f"s. To find the electron configuration of any atom, just count! IE, Magnesium is 1s2 2s2 2p6 3s2. One just goes left to right and adds up each element as an extra electron in the orbitals of the sub levels of the element, and follows the filling pattern (included here http://i.imgur.com/ZBKfm.gif).

Now if we get down to iron, we see it fills the following: 1s2 2s2 2p6 3s2 3p6 4s2 3d6 (in order of filling, not of energy). if we had an element with a few less electrons, such as Vanadium the configuration would end in 3d3. But we need to keep in mind that although the sublevel d can hold 10 electrons in total, these are arranged in orbital pairs of 2 each, therefore sublevel d has only 5 orbitals (similarly, the s sublevel has only one orbital, p has 3, f has 7).

Orbitals can contain 2 electrons at max, however in filling a sublevel's orbitals, they are filled with only 1 spin state of electron until there are no other orbitals without single electrons. That is to say, when filling up the d sublevel we put one electron in the -2 orbital, then one in the -1 orbital, then one in the 0, one in 1, one in 2* BEFORE we start pairing up the electrons in their orbitals. After which we add the second in -2 then -1, then 0, and so on until all the orbitals are full. This is because it takes less energy to occupy different orbitals than pair up. But once the point is reached where there are no unoccupied orbitals in the sub level, they pair up. Now since there are 5 orbitals in the d sublevel, and Fe is 6 atoms into the sublevel, it has 6 electrons in that sub level. Those first 5 each occupy one orbital each, and the 6th electron is paired up with the other in the -2 orbital. Thus, 4 electrons are left unpaired in their orbitals.

*:this is the third quantum number by the way, the first quantum number, "n" is energy level, second is sublevel, with s being 0, p being 1, d being 2, f 3 (l), third is orbital location (ml), which is measured in orbitals away from the "center" of the sublevel's orbitals, and the final is spin state, +/-1/2 (ms).

This is fairly complicated and I'm a shitty teacher, so don't hesitate to ask for any clarification.

3) There is no 6g sublevel, as far as I know

8] it isn't -.08 compared to -.03. It is 8.0*10^-20 J, compared to 3.5*10^-20 J. if we rearrange these we see 8~/(10^20) J compared to 3~/(10^20) J. They are both multiplied/divided by the same amount to the point where they become tiny tiny numbers, but 8 is still larger than three in terms of joules. Since answer A still shows a smaller energy amount than C, A is longer in terms of wavelength, and the correct answer.

9) The trend for atomic radius size is that as you add energy levels to the atom, size increases hugely (going down the table), but as you go from left to right, each electron that is added is matched by an additional proton added. The proton added actually pulls in the electrons more than adding an extra electron would push them out.

10) Yes, higher frequency is more energy, but that has little to do with the concept this problem addresses. The thing is more energy is contained in the 5th and 2nd energy levels of the electron than the 4th and 1st, so while both changes involve the same change in energy level, there is more energy in the 5th and 2nd levels so more is released as the electron makes that transition.

11) It is Zn2+, because as we move up in electron count (according to the filling diagram above) the 3d orbitals are filled after the 4s orbitals, and thus 3d10 marks position. Now I can see you think that removing two electrons from the configuration would correspond to a configuration ending in 3d8, which is Ni, but since electrons are removed in terms of increasing ionization energy* (it is easier to remove electrons farther out from the atomic nucleus), and the 4s orbitals have the least amount of energy, it is those electrons which are removed and do NOT denote position.

*: the filling diagram has an arrow pointing dowanwards denoting increasing energy. This is NOT ionization energy, it is the energy contained in the orbits of the electrons.

12) I'm leaning more towards A now actually, because I think the sub xy may correspond to orbital position within the sub level (that is, ml) and y may be spin state. Still not sure though so meh :S

15) Same reasoning as above

17) You are right it is D, gotta love 2 am chem

18) Nope, I'm wrong it is actually B. I forgot this is allllll done in kelvin, not celsius. Another case of the brain sapping sleepies.

19) (5L*9atm+10L*6atm)/(5L+10L)=7 atm

20) Don't need PV=nRT, any mole of gas at STP occupies 22.4 liters of space (around there). (1.5mol C2H4)*(3 O2/C2H4)*22.4=100.8 ~> 101

21) (35.1/16)*.08206*K=5.2*2.7 ==> 2.2*.08206*K=14.04 ==> 14.04/0.181=K, K~78.1

23) the equation H=q+pv (pv=w) applies, and since H is the system, a positive W means there is work being done on it, so B and D are out, as is A since Q is positive.... I guess C yea.

24) Temperature change is based on the specific heat capacity value, which is a constant so yes it is linear.

is a 0 degree celsius piece of metal exposed to x amount of heat going to change in temp as much as another sample of the same metal at 40 degrees celsius?

Since the metals are the same they have the same specific heat capacity, and assuming the masses of the samples are the same (which I assume you meant in the wording of your problem), yes. The temperature will increase from 0 degrees just as much as if it started at 40 degrees.

[GRAWRG.]

2. yeah i get it now. i was making it too complicated. the n and l and ml stuff i'll just have to memorize... has nothing to do with teaching :/
3. thats what i meant
8. i was shortening the numbers for eases sake. it doesnt matter if it's -.08 compared to -.03 or -.008 compared to -.003. the idea is still the same. -.08 is the smaller number. so 8.0*10^-20 is the smaller number... right?
9. this helps.
10. how/why?
11. your answer confuses me. idk where "removing 2 electrons" is coming from. where i do the configurations for Zn2+ i get the same as Ni. what is the config for Ni if it isnt as stated in the problem? and why is that its configuration?
18. ok, so it is as simple as VT=VT ... with v=liters and t=kelvin?
19. right, i vaguely remember that formula. it's a prettier version of what i did. thanks.
20. got it.
21. got it. i was tired when i did this too...
24. that's interesting. i had water on my mind for some reason. and i dont think it applies here. possibly because water isnt an element, and more because... i was thinking of how hot water freezes faster than cold water. which was just something i was told from someone reliable. but now that ive just looked it up, it's a strange and certainly not consistent event. so meh. okay, thanks.

[JuliusCaesar]

8] Nothing is negative, why are you using negative numbers? lol
10) there is more energy in energy levels 5-2 than in 4-1, because those in 5-2 are, as a whole, farther out from the atom, thus their electrons contain more energy to stay that far out, although the equation is based on the change in energy level, the location of the levels is important too.
11) The configuration for Ni is 1s2 2s2 2p6 3s2 3p6 4s2 3d8, not 1s2 2s2 2p6 3s2 3p6 3d10 as the problem states, because when finding configurations you take the atom's electron number and just fill up the orbits in the order I posted in the second link/the explanation I gave. But when an atom is ionized, as Zinc is, its electrons with the lowest attraction to the nucleus are removed, in this case the 2 in the 4s orbital, since they are furthest out they are the least attracted to the nucleus (the amount of energy needed to remove the outermost electron=ionization energy). While the electron count of Zn2+ and Ni are the same, due to the way the electrons are filled and then removed during ionization the configurations are different.
18] No, V/t=V/t.
24) uhhhhh I don't think that is true.

[GRAWRG.]

wait, back to specific heat since im on wiki trying to find the formula im missing. theres a table here of specific heat capacities, and it says "at 25 degrees unless otherwise noted" ... which strongly implies that specific heat capacity varies based on temperature. o.o

25. yay, finally got that. had to look at my lab manual for the equation 0.o qh20 = qmetal x deltaTmetal x massmetal
ROFL, just scrolled down and saw that you totally explained that. wow i suck.

i'll probably just look at the rest on my own much later. atm im trying to find out what the test questions will be o.o

OH. your new post just popped up. duh! hug knows what i was thinking.

10. what you say makes sense, but this is what i have in my head - http://www.google.com/imgres?um=1&hl=en ... =80&ty=138

18. what evsss, lol.
24. [at beginning of post]

[JuliusCaesar]

Hmmm where did you find that interesting graphic? Anyway I asked my dad about it since I couldn't find anything even remotely relevent to what I was looking for, you're right. Turns out that the difference in the energy contained in different levels is SMALLER farther out, and larger closer in, so the transition from 4 to 1 actually has more energy. And if the specific heat does vary it must be exceedingly minute, because I don't think I have ever had to adjust the value, excepting after phase changes of course. That 25 degrees C is standard temperature fore many enthalpy related equations......perhaps it is just included there for continuity? Idk

[GRAWRG.]

i just google imaged energy levels. thats the pic my teacher drew on the board when we were going over this in class. i forget the explanation, but it made sense.
anyway, i just found some honors chem 2 teacher's "study guides" that contain all of the questions from my past exams. so im gonna study from that now o.o

[JesusRocks765]

Lol, I didnt think anyone would be bored enough to actualy do Grawrg's homework - of course it's JC

[GRAWRG.]

it isnt my homework... it's me studying. and i practically begged for jc's help 0.o

just ran into a question i dont get. Which of the following statements correctly describes the signs of q and w for the following exothermic process at P = 1 atm and T = 370K?

H20(g) -> H20(l)

the guide says the answer is C) q is negative and w is positive. butttt. i thought w would be negative since H20(l) has less energy than H20(g)?

[JuliusCaesar]

Q is negative because of the conditions you specified, Q represents entropy, w represents work. Now, since work is viewed from the perspective of the system and in condensing the water shrinks and pressure is lost, there is negative work since both shrink. And of course, w=pv

[JesusRocks765]

well, dont let me stop you, chem is pretty important.

[GRAWRG.]

so the answer key is a liar? o.o

[JuliusCaesar]

Erm... pressure and volume being lost...weighed against the surroundings o.O
pressure-volume is gained.....I'm confused now. I never really got that equation

[GRAWRG.]

well work is energy. and liquids have less energy than gasses. so if a gas is going to a liquid, is it losing energy. so i think logically, work should be negative. but i struggled with work, so maybe im doing it wrong.

at any rate, thank you. i'll have to give you tokens. or a kitten. or something to make up for this, lol xD

[JuliusCaesar]

lol work is work, energy is energy, and entropy is q.

E=q+w

Entropy is negative since it goes from gas to liquid, work is positive because...... ermmmmm.....hmm.....

Actually I may be thinking about delta G= delta H - T*deltaS......

I HAVE NO CLUE

NO WAIT!

http://www.shodor.org/unchem/advanced/thermo/

This says:
deltaE=q-w
MINUS WORK!
thus entropy is negative, since the system becomes more ordered in condensing to a liquid, and although it shrinks and loses pressure, since it is -w the ACTUAL sign of w is positive. THERE! lol

[GRAWRG.]

they all look the same to me, lol. heat is energy. work is energy. energy is energy. all of the letters just seem to be about forms and changes.

but anyway, what? 0.o i feel like that's grasping for an explanation. cause if deltaE= q-w the sign for w still isnt negative. cause then you'd have the equation deltaE=q+w

[JuliusCaesar]

Idk, its all very wishy washy it seems. Ignore it and hope they don't ask questions about it on the test xD

Edit: Physics is hard D: I miss chem...

[GRAWRG.]

how hard?

i was thinking of taking bio principles physics and differential equations next semester

but if you're hating on physics compared to chem, and you grew up with chem... it shouldnt really be a big change in effort for me?

[JuliusCaesar]

Well....how good are you with math? I don't mean knowledgeable, I mean creativity in flipping around equations and relating like 6 different possible equations with different situations.

[GRAWRG.]

sounds like fun to me.

[fredfredburger]

didnt read and i dont agree

[GRAWRG.]

looks like we have another dumbfuck of a troll roaming the forums...

[JuliusCaesar]

Don't agree with what lmfao? Chemistry? Ok just take some cyanide and see how well you do without it.

[GRAWRG.]

no no what he meant was that he doesnt agree with not being a human waste of space.

[GRAWRG.]

i got an 80. there were a few people who got over a 100, and the class average was in the 50's. so i guess i did well comparatively, but im disappointed cause i was barely holding an A and now im not :/

at any rate, thanks!

[JuliusCaesar]

Lol savor it anyway, chem is a very hard class for a lot of people. I know people who would punch themselves in their nads a few times for an 80 in chem atm.

[GRAWRG.]

our chem teacher checked the answer key last nite. he thought it might have been wrong because of the grades o.o

but it wasnt. after a 20 point curve, the average grade was in the 50's.