AVHS . AP ChemisFy
Pd
Name
First Semester Final
AP FRQ Practice
5 Br@ql + BrO{taq) + 6 W@d
1)
-
- Set {
3 Brz,l0 + 3 HrOal
In a study of the kinetics of the reaction represented above, the following latajyere obtained at 298 K.
of
Experi
Initial
Initial
lnitial
ment
lBr-l
fH.l
(mol L-')
tBrotl
(mol Li)
(molL-1).
Disappearance of
BrO -(mol L-l s-')
I
0.00100
0.00500
0.100
2.50x104
2
0.00200
0.00500
0.100
5.00x104
3
0.00100
0.00750
0.100
3.75x104
4
0.00100
0.01500
0.200
3,00x10-3
Rate
(a) From the data given above, determine the order of the reaction for each reactant listed below. Show your
reasoning.
(i) B.
(ii)
BrOr-
(iii)If
(b) Write the rate law for the overall reaction.
(c)
Determine the value of the specific rate constant for the feaction at298 K. Include the corrrlct units.
2) A rigid 5.00 L cylinder contains 24.5 g of Nzfst and 28.0 gof Ar1sl
(a) Calculate the total pressure, in atm, of the gas mixture in the cylinder at298K.
(b) The temperature of the gas mixture in the cylinder is decreased to 280 K. Calculate each of the following..
(i) The mole fraction of N2(l in the cylinder.
(ii) The partiat pressure, in atm, ofNz(g) in the cylinder.
(c) If the cylinder develops a pinhole-sized leak and some of the gaseous mixture escapes, would the ratio
+lg
Orts)
in the cylinder increase, decrease, or remain the same? Justify your answer.
A different rigid 5.00 L cylinder contains AJ76 mol of NOfs) at298 K. A 0.176 mol sample of Orlgl is added to
the cylinder, where a reaction occurs to produce NOrfgt.
(d) Write the balanced equation for the reaction.
(e) Calculate the total pressure, in atm, in the cylinder at298 K after the reaction is complete.
3) Propane, C,FI*, is a hydrocarbon that is commonly used as fuel for cooking.
(a) Write a balanced equation for the complete combustion of propane gas, which yields COzG) andHzO?l.
(b) Calculate the volume of air at 30oC and 1.00 aftnosphere that is needed to burn completely 10.0 gam3 of
propane. Assume that air is 21.0 percent Or by volume.
(c) The heat of combustion of propane is -2,220.1 kJ/mol. Calculate the heat of formation, L,Hf, of propane
given that L,H1" of HrO ft) -285 .3 kJ/mol and LHf of CA zk) : -3 93. 5 kJ/mol.
(d) Assuming that all of the heat evolved in burning 30.0 grams of propane is transferred to 8.00 kilograms of
water (specific heat: a.1S J/g'K), calculate the increase in temperature of water.
:
4) Suppose that a stable element with atomic number 119, symbol Q, hasbeen discovered.
(a) Write the ground-state electron configuration for Q, showing only the valence-shell electrons.
(b) Would Q be a metal or a nonmetal? Explain in terms of electron configuration.
(c) On the basis of periodic trends, would Q have the largest atomic radius in its group or would it have the
smallest? Explain in terms of electronic structure.
(d) What would be the most likely charge of the Q ion in stable ionic compounds?
(e) Write a balanced equation that would represent the reaction of Q with water.
(0 Assume that Q reacts to form a carbonate compound.
(i) Write the formula for the compound formed between Q and the carbonate ion, CO32-.
(ii) Predict whether or not the compound would be soluble in water. Explain your reasoning.
5) A sample of dolomitic limestone containing only CaCO3 and MgCO: was analyzed.
(a) When a 0.2800 grnm sample of this limestone was decomposed by heating, 75;0 milliliters of COz at 750
mm Hg and 20'C were evolved. How many grams of COz were produced?
(b) Write equations for the decomposition of both carbonates described above.
(c) It was also determined that the initial sample contained 0.0448 gram of calcium. What percent of the
limestone by mass was CaCOs?
(d) How many grams of the magnesium-containing product were present in the sample in (a) after it had been
heated?
6)
Compound
Name
Compound
Formula
L,I{,^p
(kJ mol't)
Propane
CHsCHzCHT
19.0
Propanone
CHTCOCHT
32.0
1-propanol
CHTCHzCHzOH
47.3
Using the information in the table above, answer the following questions about organic compounds.
(a) For propanone,
draw the complete structural formula (showing all atoms and bonds);
(ii) predict the approximate carbon-to-carbon-to-carbon bond angle.
(b) For each pair of compounds below, explain why they do not have the same value for their standard heat of
vaporization, Affu"p. (You must include specific information about both compounds in each pair.)
Propaneandpropanone
(ii) Propanone and l-propanol
(c) Draw the complete structural formula for an isomer of the molecule you drew in, part (a) (i).
(i)
(i)
(d) Given the structural formula for propyne below,
H
rl
H-C-C=C-H
I
H
(i)
(ii)
indicate the hybridizationof the carbon atom indicated by the arrow in the structure above;
indicate the total number of sigma (o) bands and the total number of pi (n) bonds in the molecule