June 2007 chemistry

clicheusername57 · June 4, 2007, 6:50pm

I dentify the Delta H in each of the following reactions: (four sepa-rate questions)

Delta H sublimation: CO2(s) –> CO2(g)
Delta H fusion: H2O(s) –> H2O(l)
Delta H combustion: O2(g) was a reactant
Delta H combination: Na + Cl –> Nacl

does anyone remember if there was H2O (l) –> H2O (g) because I am worried I put it down. That’s a stupid mistake I would make.

PKswmr76 · June 4, 2007, 6:53pm

“If you double pressure and double temperature, the volume will stay constant. Because pressure and temperature are inversely pro-portional. TTCE.”

actually starport, I’m pretty sure the second statement said that pressure and volume were directly proportional and that temperature and volume were indirectly proportional, which is not true (F) because PV is indirectly proportional and V/T is directly proportional

I could have read the question wrong though, anyone else agree with me?

clicheusername57 · June 4, 2007, 6:54pm

Ones no one can recall but nonetheless existed: Something mentioning NaOH. Something mentioning H2O2.

PKswemr76: I’m relatively positive it said that pressure and volume were inversely proportional and temperature and volume were directly proportional. But I too could be wrong…hmm

Pinki10583 · June 4, 2007, 6:55pm

Some of the answers are pictures which wont show up but this is one of my newer versions of the test

*Note, this ‘study guide’ complies with the regulations asserted by the College Board as they contain no copy righted material and are intended for educational purposes only, not for discussion involving scores, questions from the June 2007 test and/or any violations of the guidelines signed by the test taker.

1) What is the main component in glass?

SiO2

2) What is the lewis-dot structure of HCN?

3) What would be the formula of CxOy if it is added to one mol of oxygen and produces .5 moles of carbon dioxide?

C2O3

4) The oxidation states in aluminum sulfide?
Aluminum: +3
Sulfur: -2

5) Which of the following is a hydration reaction?

CuSO4 + H2O CuSO4X5H20

6) Which substance is blue?

Copper sulfate pentahydrate

7) Which substance is white?

Ammonia nitrate

8) A catalyst does what to A + B  C?

Speeds up the forward and reverse reactions

9) forms a precipitate?

adding HCL to AgNO3

10) Most accurate for measuring 27.29 mL of a liquid?

Burette

11) Which of the following are needed to measure specific heat?
I. calorimeter
II. balance
III. thermometer
I,II, and III

11) The percentage by mass involving Cd, O and H:

Cd(OH)2

12) Why is there a huge “Drop off” in the chart about the volume of NH3?
Because of condensation

13) Which of the following would you never do in lab? (Lab safety Question)

I. Never pour water into Acid
II. Return unused chemicals to original container
III. Always were eye protection

I, II and III

14) Which of the following is amphoteric?

HCO3

Identify the Delta H in each of the following reactions: (four separate questions)

15)Delta H sublimation: CO2(s) –> CO2(g)
16)Delta H fusion: H2O(s) –> H2O(l)
17)Delta H combustion: O2(g) was a reactant
18)Delta H combination: Na + Cl –> Nacl

19) which equation is an oxidation reduction reaction?
Cu+2 + Fe –> Cu + Fe+2

20) Which is Polymerization?

(im not sure it was either C, two hydrocarbons, or E)

21) Which is a combustion reaction?

22) What happens when you add CL ions to Silver Nitrate?

A precipitate will form

23) Graff Pressure vs. Volume:

24) Graff Volume vs. Temperature:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
101) Adding NaCl to a saturated solution makes no change in concentration T because NaCl is soluble at 25 degrees T

102) Water is a poor conductor T because Water only ionizes slightly T, CE

103) NH3 is a better base then Water T Because (I don’t remember the second statement but it was T), CE
104) H2S is polarT because it has two lone electron pairs T, CE

105) When you run electrons through pure neon gas it releases light T because when electrons return to their ground state photons are released T, CE

106) Metals are good conductors of electricity T Because metals can form both positive and negative ions F (im not so sure about the second statement)

107) PH3 is trigonal pyramidal T because the lone pairs creates mutual repulsion T, CE

108) Elements in the same family form the same types of compounds T Because they have the same number of valence electrons. T, CE

109) As you go down in a family the radius of the atoms increases T Because adding neutrons to the nucleus increases radius. F

110)If you double pressure and double temperature, the volume will stay constant T Because pressure and temperature are inversely proportional. T, CE


&lt;p&gt;25) How much energy does it take to make 18 of water? (Heat of combination is 334/g)&lt;/p&gt;

&lt;p&gt;6012 KJ &lt;/p&gt;

&lt;p&gt;26) Which of the following is not part of the modern atomic theory?&lt;/p&gt;

&lt;p&gt;Atoms are indestructible&lt;/p&gt;

&lt;p&gt;27) The percentage by mass question of Carbon (75%) and Hydrogen (25%)?&lt;/p&gt;

&lt;p&gt;CH4&lt;/p&gt;

&lt;p&gt;28) Which element is the hardest to oxidize?&lt;/p&gt;

&lt;p&gt;Fluorine&lt;/p&gt;

&lt;p&gt;29) Which of the following elements is radioactive?&lt;/p&gt;

&lt;p&gt;At (astatine)&lt;/p&gt;

&lt;p&gt;30) Which of the following is a conjugate base in the provided reaction?&lt;/p&gt;

&lt;p&gt;CO3-2&lt;/p&gt;

&lt;p&gt;31) The PH of a solution changes from 4 to 2, the [H+] is now what times greater?&lt;/p&gt;

&lt;p&gt;100&lt;/p&gt;

&lt;p&gt;32) A question where the volume stays the same but the temperature and pressure change:&lt;/p&gt;

&lt;p&gt;(Answer) 400/300&lt;/p&gt;

&lt;p&gt;33) Which of the following has the lowest first ionization energy?&lt;/p&gt;

&lt;p&gt;K (potassium)&lt;/p&gt;

&lt;p&gt;34) Which of the following is not an acid?&lt;/p&gt;

&lt;p&gt;C2H6&lt;/p&gt;

&lt;p&gt;35) There was one about the partial pressure of oxygen and nitrogen:&lt;/p&gt;

&lt;p&gt;(answer) oxygen has 3X nitrogen&lt;/p&gt;

&lt;p&gt;36) What is the oxidation state is At in H3AtO4?&lt;/p&gt;

&lt;p&gt;+5&lt;/p&gt;

&lt;p&gt;37) At STP there are 3 X 10^23 molecules of a gas in a container, which of the following could be the substance?&lt;/p&gt;

&lt;p&gt;22 grams of CO2 &lt;/p&gt;

&lt;p&gt;38) Which element could be represented by X in the molecule XH3?&lt;/p&gt;

&lt;p&gt;P (phosphate)&lt;/p&gt;

&lt;p&gt;39) How many grams of NaOH is needed to form a .1M 25.0 mL solution?&lt;/p&gt;

&lt;p&gt;.1&lt;/p&gt;

&lt;p&gt;40) .500 mL of some liquid (density 2.50 g/ml) and you add .0431 g of some solid. Which of the following is a correct messurement of the mass?&lt;/p&gt;

&lt;p&gt;1.29g&lt;/p&gt;

&lt;p&gt;41) What is the mass of acetic acid (there was some question like this, I don’t remember the question though)?&lt;/p&gt;

&lt;p&gt;was 6.0g&lt;/p&gt;

&lt;p&gt;42) which of the following is true for the Elements 21-28?&lt;/p&gt;

&lt;p&gt;They partially fill in the 3d shell&lt;/p&gt;

&lt;p&gt;43) Which of the following is a noble gas?&lt;/p&gt;

&lt;p&gt;Kr&lt;/p&gt;

&lt;p&gt;44) Which of the following is found in nature as a diatomic gas?&lt;/p&gt;

&lt;p&gt;Nitrogen&lt;/p&gt;

&lt;p&gt;45) Which of the following is a transition metal?&lt;/p&gt;

&lt;p&gt;Fe&lt;/p&gt;

&lt;p&gt;Adding an acid to a solution containing CO3 2-. A gas is evolved.&lt;/p&gt;

&lt;p&gt;46) Adding heat to a closed vessel increases reaction rate because:
I. More collisions
II. Activiation energy is lowered
III. More molecules have the right about of energy to collide. 
I and III&lt;/p&gt;

&lt;p&gt;47) SO2 + O2   SO3 + heat
Which of the following would increase the amount of SO3 production?&lt;/p&gt;

&lt;p&gt;increasing the concentration of O2&lt;/p&gt;

&lt;p&gt;CS2 + O2 -&gt; 
48) The reaction above yields:&lt;/p&gt;

&lt;p&gt;1 mol of CO2 and 2 mol of SO2&lt;/p&gt;

&lt;p&gt;49) There was some combustion question where it asked for the coefficient of O2:&lt;/p&gt;

&lt;p&gt;(Answer) 13&lt;/p&gt;

&lt;p&gt;50) which of the following is not an acid?&lt;/p&gt;

&lt;p&gt;C2H6&lt;/p&gt;

&lt;p&gt;51) There was a gas question where you had to find the temp:&lt;/p&gt;

&lt;p&gt;(answer) 75 K&lt;/p&gt;

&lt;p&gt;52) 1 mol of water is formed from H2 and O2 and it releases 280kJ. How much heat would be released with .5 mol of water?&lt;/p&gt;

&lt;p&gt;140 kJ.&lt;/p&gt;

&lt;p&gt;53) Ca2+, K+, Ar, S2-, Cl- have the same number of:&lt;/p&gt;

&lt;p&gt;electrons&lt;/p&gt;

&lt;p&gt;54) What is the pH of a 0.01 M solution of HNO3?
2&lt;/p&gt;

PKswmr76 · June 4, 2007, 7:05pm

“110)If you double pressure and double temperature, the volume will stay constant T Because pressure and temperature are inversely proportional. T, CE”

are you sure your second statement is what was actually on the test?

i remember thinking the answer to that was TTCE, but I came back to it and when I read it closely I think I remember seeing that the second statement was actually false…I could have just misread the statement but I don’t think so

clicheusername57 · June 4, 2007, 7:08pm

I read this on another thread and thought it might be interesting to all of you, seeing as we have the majority of the test up there ^^

"From my CB book:

78-85: 800
76-77: 790
74-75: 780
72-73: 770
70-71: 760
68-69: 750
67: 740
65-66: 740
63-64: 720
61-62: 710
59-60: 700" thats for chem, they didnt specify what year the book was from though.

jenkster · June 4, 2007, 7:10pm

PK, I agree that it was TF.

PKswmr76 · June 4, 2007, 7:12pm

nice, i guess im not crazy after all :-)))

tux08902 · June 4, 2007, 7:17pm

It was TF, not TTCE. I worked it out, and the second statement was completely wrong.

tux08902 · June 4, 2007, 7:18pm

This anyone can contest because graduated cylinder was also an option, therefore, I think it will be thrown out.

tux08902 · June 4, 2007, 7:22pm

This is wrong. You always want to wear eye protection. And again, I is also contestable. When you do dilutions and such, you usually measure out the liquids you need. Then you start off with some water in a volumetric flask. You then add your measured acid into the flask. Then you top it off with water till the end mark. My teacher said this had something to do with the way the acid settled in the water and the density difference.

tux08902 · June 4, 2007, 7:24pm

I will contest this as well. This was mentioned a while ago in this thread, so I asked some of my friends to conform my suspicions. The second statement did not say electrons. It said excited atoms release photons as they return to a lower energy state. That’s very poorly worded. And, technically, that isn’t true.

tux08902 · June 4, 2007, 7:28pm

This is correct because metals have metallic bonds; they form a sea of electron. There are no ions in metallic bonds.

PKswmr76 · June 4, 2007, 7:28pm

the answer is buret because it has more significant figures, i asked my chem teacher today

PKswmr76 · June 4, 2007, 7:29pm

are the photons not being released from the atoms? if they aren’t, from where are they being released?

jenkster · June 4, 2007, 7:29pm

There are such things as excited atoms. It just means that its electrons are on higher energy levels.

For example, you can say “When a photon strikes hydrogen, it is excited.”

PKswmr76 · June 4, 2007, 7:31pm

so do you (jenkster) think that the answer to that was ttce?

tux08902 · June 4, 2007, 7:32pm

I’ve seen very accurate graduated cylinders. I’ve used burets as well, and the ones I’ve used don’t have any different significant figures than the graduated cylinders I’ve used. And we were preparing for Chemistry Olympics, my chem teacher said that the only reason you’d want to use a buret is to help with distributing the liquids, help with the mixing after you cap it. Otherwise, for accuracy either would be equally sufficient.

Fine, I guess I read too much into the photon/atom question.

So, out of those 66, I have 1 omit, 3 wrong. Not bad at all.

clicheusername57 · June 4, 2007, 7:32pm

Yes, I asked my chemistry teacher about the atoms/electrons. She said referring to atoms as excited is not wrong perse but the more detailed answer is that electrons are being excited. Tux I agree with you about the safety one. I don’t remember the exact wording of statement one but I said that only III was correct. I believe it said 50-ml graduated cylinder and 50-ml buret, of which 50-ml buret is more precise

jenkster · June 4, 2007, 7:33pm

I think it is, but there were too many details in both statements (all of which I don’t remember), so I’m not entirely sure.

June 2007 chemistry

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