1. Matching: match the items in the right column by writing in the CAPITAL letter of a selection from the items in the left.
A. = _____ T, P
B. LEO _____ (S.H.)(m)(DT)
C. q + w = _____ 1.00 atm
D. DHrxn = _____ P, V
E. PV = _____ GER
F. Boyle _____
G. qcal = _____ 0.08206
H. 760 Torr = _____ nRT
I. = _____ -
J. Gay-Lussac _____
K. K = _____ + 273
L. R = _____ DU
2. a. What is the difference between an electrolyte and a non-electrolyte, and how does the Arrhenius theory account for this?
b. What is the difference between a strong electrolyte and a weak electrolyte. Cite an example of each, and explain how the Arrhenius theory accounts for the difference.
3. When aqueous solutions of Hg(NO3)2 and NaI are mixed, an orange precipitate forms. Given that all Na+ compounds are soluble, deduce and write balanced molecular, ionic, and net ionic equations representing the observed reaction.
4. Consider the following reaction (unbalanced) that takes place in acidic solution:
Cr2O72- (aq) + Cl1- (aq) + H1+(aq) à Cr3+(aq) + Cl2 (g) + H2O
a. Assign oxidation numbers to
each oxygen in Cr2O72- - _____
each chromium in Cr2O72- _____ each chromium in Cr3+ _____
each chlorine in Cl1- _____ each chlorine in Cl2 _____
hydrogen in H1+ _____ each hydrogen in H2O _____
each oxygen in H2O _____
b. In this reaction, which element gets oxidized?_____ Which element gets reduced? ______
Which substance is the oxidizing agent? ________
c. Balance the equation
___ Cr2O72- (aq) + ___ Cl1- (aq) + ___H1+(aq) à ___ Cr3+(aq) + ___ Cl2 (g) + ___H2O
5. If a particular system gives off 643 J of heat and does work equivalent to 246 J, what is its overall DU?
6. Consider two 5.00 L containers, one holding Cl2(g) and the other holding CH4(g), each at the same temperature and pressure. When compared to the Cl2, would the CH4 have a larger, smaller, or same
a. number of moles of gas? ______________
b. total mass of gas? _____________
c. average translational kinetic energy? ____________
d. average molecular speed? _____________
Calculate below the numerical value for this relative rate of diffusion of CH4 compared to Cl2:
e. If the temperature of either container were increased, and the volume could expand or contract so as to keep pressure constant, what would happen to the volume of the gas in that container, and WHY? Explain in terms of kinetic-molecular theory.
7. If 2.4 L of gas at 740 Torr is increased to 5.6 L while its temperature is increased from 100 to 200 , what would be the new pressure of the gas?
8. A piece of unknown metal having a mass of 15.3 g is taken from an oven at 116 ºC and immersed in 95.5 mL of water (S.H. = 4.184 J g-1 ºC-1; d = 1.00 g/mL) at 23.9 ºC in a calorimeter cup. The water temperature rises and levels off at 42.4 ºC. What is the specific heat of the metal?
9. In a lab experiment, 2.72 g of a metal reacts with excess hydrochloric acid to produce hydrogen gas, H2.
a. If 1,040 mL of hydrogen are collected by water displacement at a barometric pressure of 761 Torr and a temperature of 23 °C, calculate the moles of H2 collected.
(Vapor pressure of water at 23 °C = 21 Torr)
b. Given that 2.75 g of metal were reacted, calculate the molar mass of the metal, assuming the reaction followed this equation: M(s) + 2 HCl(aq) à H2(g) + MCl2(aq)
10. Consider the following reaction:
5 C (s) + 2 SO2 (g) à CS2 (l) + 4 CO (g) DH = ?
a. Given the information below, calculate DH for the reaction as written.
b. Based on your answer to 10.a., is the reaction endothermic or exothermic? ___________
c. Based on your answer to 10.a., how much heat is involved in the reaction of 30.0 g of carbon with sufficient SO2?
11. Determine the enthalpy change for the oxidation of ammonia:
4 NH3 + 5 O2 4 NO + 6 H2O DH = ?
from the following data:
N2 + O2 2 NO DH = + 180.5 kJ
N2 + 3 H2 2 NH3 DH = – 99.2 kJ
2 H2 + O2 2 H2O DH = – 571.6 kJ