Chapter 10
Under what conditions will "q" and "w" be negative numbers?
When a system loses heat, "q" is negative
When a system does work to its surroundings, "w" is negative
What is the temperature and pressure value at STP?
273 K; 1 atm
By reversing a chemical equation, what happens to the equation's ΔH?
Take the opposite sign of the original ΔH
By doubling the amount of pressure on a container, what happens to the volume of a container?
Volume will decrease by two
How much heat is needed to raise a 0.30 g piece of aluminum from 30℃ to 150℃? (Specific heat capacity of aluminum: 0.9 J/℃g)
32 Joules
How can you achieve a higher density of a gas? (Change what two things?)
1. Lower the temperature
2. Raise the pressure
Use: N2(g) + O2(g) → 2 NO(g) ΔH = 180.6 kJ
If 558 kJ of energy is supplied, what mass of NO can be made?
185 grams of NO
A container with two gases, helium and argon, is 30.0% by volume helium. Calculate the partial pressure of helium and argon if the total pressure inside the container is 4.00 atm.
1.20 atm He; 2.80 atm Ar
Calculate the overall ΔH for the equation: C2H2(g) + ⁵/₂ O2 (g) → 2CO2(g) + H2O(g)
C2H6(g) → C2H2 (g) + 2 H2(g) ΔH = 283.5 kJ
H2(g) + ½ O2(g) → H2O(g) ΔH = –213.7 kJ
2 CO2(g) + 3 H2O(g) → C2H6(g) + ⁷/₂ O2(g) ΔH = 849 kJ
ΔH = -705 kJ
How many molecules are there in 985 mL of nitrogen (N2) at 0.0°C and 1.0x10-6 mmHg?
3.48 x 1013 N2 molecules
Calculate the ΔHrxn from the ΔHf for the following reaction: CH4(g) + 2 O2(g) -----> CO2(g) + 2 H2O(l)
ΔHf of O2 = 0
ΔHf of CH4 = -74.8
ΔHf of CO2 = -393.5
ΔHf of H2O(l) = -285.8
ΔHrxn = -891.1 kJ
Determine the density of CO2 at 745 mmHg and 65℃.
1.55 g/L
How much heat will be released when 6.44 grams of sulfur reacts with excess O2 to form SO3?
ΔH = -791.4 kJ
-79.5 kJ
What is the density of an ideal gas with a molecular mass of 50 g/mol at 2 atm and 27 °C?
4.06 g/L
Calculate the overall ΔH for CO2(g) → C(s) + O2(g) using the following equations:
H2O(l) → H2(g) + ½ O2(g) ΔH = 643 kJ
C2H6(g) → 2 C(s) + 3 H2 (g) ΔH = 190.6 kJ
2 CO2(g) + 3 H2O(l) → C2H6(g) + ⁷/₂ O2(g) ΔH = 3511.1 kJ
ΔH = 886 kJ
Using the following equation, CaCO3(s) → CO2(g) + CaO(s), determine how many grams of calcium carbonate will form from 3.45 liters of carbon dioxide? Assume the reaction is done at 1.0 atm and 298 K.
14.1 grams
Calculate the ΔHrxn from the ΔHf for the following reaction:
NaOH(s) + HCl(g) ----> NaCl(s) + H2O(g)
ΔHf of NaOH = -426.7
ΔHf of HCl = -92.3
ΔHf of NaCl = -411.0
ΔHf of H2O (g) = -20.1
ΔHrxn = -133.8 kJ
What temperature will result when 20 g of hydrogen reacts completely with oxygen? The water that is formed during this reaction will be at a pressure of 0.938 atm and a volume of 17 liters
19.4 K
Using bond energies, calculate the ΔHrxn for: CO(g) + H2O(g) -------> CO2(g) + H2(g)
C-O bond in carbon monoxide = 1077 kJ/mol
C=O in carbon dioxide = 805 kJ/mol
O-H = 464 kJ/mol
H-H = 436 kJ/mol
ΔHrxn = -41 kJ
What volume of chlorine gas forms when 75 g of phosphorus pentachloride decomposes? The other product is phosphorus trichloride. The temperature is 200ºC and the pressure is 1.48 atm.
9.47 L