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Chemistry 1411
Sample EXAM # 2
Chapters 4, & 5
Activity Series of Metals in Aqueous Solution
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CHEM 1411 Exam # 2
(Chapters 4, & 5)
Part I- Please write your correct answer next to each question number.
____ 1. Which of the following are nonelectrolytes in water?
(i) HF
A.
ii and iii
(ii) ethanol, C2H5OH
(iii) CH3 OCH3
B. i, ii, and iii
C. iii only
(iv) KClO3
D. ii only
____ 2. How many milliliters of 1.50 M KOH solution are needed to supply 0.125 mole of KOH?
A. 0.0833 ml
B. 0.188 ml
C. 12.0 ml
D. 83.3 ml
____ 3. Which of the following is/are soluble in water?
(i) NiCl2
A. iv only
(ii) Ag2S
(iii) Cs3PO4
B. i, ii, and iii
C.
(iv) (NH4)2SO4
i, ii, and iv
D. i, iii and iv
____ 4. Which of the following reactions will occur?
(i)Ni(s) + Zn2+(aq) 
(ii)Pb(s) + Ag+(aq) 
(iii)Zn(s) + Ca2+(aq) 
(iv)Al(s) + Fe2+(aq) 
A.
i only
B.
ii only
C. ii and iv only
D. i and iii only
____ 5. Which of the following is a weak base?
A. NaOH
B. Ca(OH)2
C. NH4OH
D. RbOH
____ 6. Which of the following gas has higher density at STP condition?
A. CH4
B. Cl2
C. CO2
D. O2
____ 7. How many moles of N2 gas occupy 11.2 liters volume a STP condition?
A. 1.0 mol
B. 2.0 mol
C. 0.50 mol
____ 8. Which of the following is/are not characteristic of gases?
I. high density
II. formation of homogeneous mixtures
A. I only
B. I and III
C. I, II, and III
D. cannot be determine
III. low intermolecular forces
D. II and III
____9. An unknown gas "X" effuses two times faster than a sample of SO3(g) through a porous container.
Which of the following is the unknown gas ?
A. H2
B. CH4
C. Ne
2
D. Ar
____10. Which of the following is not a statement of Boyle's law? All statements assume constant
temperature and amount of gas.
B. V α 1/P
A. P = constant/V
C. P/V = constant
D. PV = constant
_____ 11. All of the following are weak acids except
A. HCNO
B. HBr
C. HF
D. HNO2
E. HCN
_____ 12. How many grams of NaCl are contained in 350.ml of a 0.250 M solution of sodium chloride?
A. 41.7g
B. 5.12g
C. 14.6g
D. 87.5g
E. None of these
_____13. Consider the reaction; Zn + H2SO4 → ZnSO4 + H2 . Which element (if any) is oxidized?
A. zinc
B. hydrogen
C. sulfur
D. oxygen
E. None of these
_____14. In which of the following does nitrogen have an oxidation state of +4?
A. HNO3
B. NO2
C. N2O
D. NH4Cl
E. NaNO2
_____15. In the balanced molecular equation for the neutralization of sodium hydroxide with sulfuric acid, the
products are:
A. NaSO4 + H2O
D. Na2 +2 H2O
B. NaSO3 + 2H2O
E. Na 2 SO4 + 2H2O
C. 2NaSO4 + H2O
_____16. What volume of 18.0 M sulfuric acid must be used to prepare15.5L of 0.195 M H2 SO4?
A. 168 ml
B. 0.336L
C. 92.3 ml
D. 226 ml
E. None of these
____17. What volume is occupied by 19.6 g of methane ( CH4) at 27 oC and 1.59 atm?
A. 1.71 L
B. 18.9L
C. 27.7 L
D. 302 L
E. Not enough data to calculate
____18. Which gas has the highest density?
A. He
B. Cl2
C. CH4
D. NH3
E. All gases the same.
____19. The mass of 1.12 liters of gas Y is found to be 6.23g. The density of gas Y is:
A. 10.6 g/L
B. 5.56 g/L
C. 15.6 g/L
D. 0.200 g/L
E. 0.180 g/L
____20. The density of Nitrogen at STP is:
A. 1.60 g/L
B. 0.800 g/L
C. 1.25 g/L
D. 0.625 g/L
E. Not enough information
____21. Order the following in increasing rate of effusion:
F2, Cl2, NO, NO2, CH4
A. Cl2 < NO2 < F2 < NO < CH4
B. Cl2 < F2 < NO2 < CH4 < NO
C. CH4 < NO2 < NO < F2 < Cl2
D. CH4 < NO < F2 < NO2 < Cl2
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E. F2 < NO < Cl2 < NO2 < CH4
PART II- ( 5 points each) Please show all your work.
1. Write a complete ionic and net-ionic equation for the following reaction.
K2CO3 (aq) + H2SO4 (aq) 
2. a) What volume(ml) of 0.115 M HClO4 solution is required to neutralize 50.00 ml of 0.0875 M
Ca(OH)2 ?
b) A solution contains 3.2 g NaOH ( MW = 40) in 20.0 ml of solution. What is the molarity of the
solution?
3. 2.50 g CO2 gas occupies 5.60 liters at 789 torr.
a) Calculate the temperature of gas in 0C.
b) What is the density of CO2 gas at STP condition?
4. What volume of O2(g), measured at 22 °C and 763 torr, is consumed in the combustion of 7.50 L
of C2H6(g), measured at STP?
2 C2H6(g) + 7 O2(g) 4 CO2(g) + 6 H2O(l)
5. A 1200 mL sample of helium gas is at a pressure of 350 mmHg and a temperature of 300 K.
What volume will this gas sample occupy if the pressure is increased to 700 mmHg and the
temperature is increased to 400 K?
6. A sample of gas has a mass of 0.311 g. Its volume is 0.225 L at a temperature of 55.0°C and a
pressure of 886 mmHg. Find its molar mass.
7. A gaseous mixture containing 1.5 mol Ar and 3.5 mol CO2 has a total pressure of 7.0 atm. What is
the partial pressure of each gas?
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1411 SAMPLE EXAM # 2 (Key)
PART – I
1. A
2. D
n = M.VL  VL = (n /M) = (0.125 mol/ 1.50 mol/L) = 0.0833 L  x 1000 = 83.3 mL
3. D
4. C
6. B
5. C
Cl2 has highest molecular weight = 71.0 gr/mol
7. C
(11.2 L) ( 1 mol / 22.4 L) = 0.50 mol N2
8. A
9. C rate(X) / rate (SO3) = ( MSO3/Mx)½  2 = ( 80 / Mx)½  4 = 80 / Mx  Mx = 80/4 = 20 Neon
10. C
11. B
12. B
13. A
14. B
15. E
16. A
g (NaCl) = M. V.MW = (0.250 mol/L)(0.350 L)(58.5 g/mol) = 5.12 g , NaCl
M1V1 = M2V2  V1 = ( 0.195)(15.5)/(18.0)  V1 = 0.168 L x 1000 ml/L = 168 ml
17. B PV = nRT = (mRT/M)  V = (mRT/MP)
= (19.6g)(0.0821 L.atm/mol.K)(300 K)/ (16 g/mol)(1.59 atm) = 18.9 L
18. B ( Cl2 = 71 g/mol , highest molecular weight)
19. B D = m /V = (6.23 g) / 1.12 L = 5.56 g/L
20. C g (N2 at STP) = ( M/22.4) = ( 28 g /mol) / (22.4 L/mol) = 1.25 g /L
21. D
PART - II
1. molecular equation: K2CO3 (aq) + H2SO4 (aq)  K2SO4(aq) + H2CO3(aq)
ioninc equation : 2K+(aq) +CO32-(aq)+ 2H+(aq) +SO42- (aq)  2K+(aq) + SO42-(aq) + H2O(l) +CO2(g)
net-ionic equation : 2H+(aq) + CO32-(aq)  H2O(l) +CO2(g)
spectator ions : 2 K+ and SO425
nbMbVb
(2)(50.00)(0.0875)
2. a) Va = ----------------- = --------------------------------- = 76.1 ml
naMa
(0.115)
(3.2/40 mole)
b) M = ----------------------- = 4 mol/ L ( mol.L -1 ) or molar
(20.0/1000 L)
3. a) PV = nR T  PV = (m/M) RT  T = ( MPV/m R)
= (44)(789)(5.60)/(760)(2.50)(0.0821) =1246 K = 973 oC 102 K
b) D(CO2) STP = (M /22.4) = 44/22.4 = 1.96 g/L
4. (7.50 L C2H6)( 1mol C2H6 / 22.4 L) ( 7 mol O2 / 2 mol C2H6 ) = 1.17 mol. O2
V = ( nRT/P) = (1.17)(0.0821)(273+22)(760)/(763) = 28.2 L
5. P1V1/T1 = P2V2/T2; V2= (P1V1/T1) x (T2 /P2); V2 = ((350 x 1200 )/ (27 + 273)) x (400 /700);
V2 = 800 mL
6. n = 9.7454 x 10 -3 mol
Molar mass = 31.9 g/mol
7. Pco2 = nco2/ nt x Pt = 3.5/5.0 x 7.0 = 4.9 atm
PAr = nAr/nt x Pt = 1.5/5.0 x 7.0 = 2.1 atm
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