Gas Law
A balloon is filled with 35.0 L of helium in the morning when the temperature is 20.0 C. By noon the temperature has risen to 45.0 C. What is the new volume of the balloon?
38.0 L
How can energy be transferred to or from a system?
Energy can be transferred as heat and/or work
What is the standard state?
T = 0 C, Conc = 1.00 M, and Pressure = 1.00 bar
What is the final temperature after 840 Joules is absorbed by 10.0 g of water at 25.0 C?
45.1 C
2C(s) + H2(g) ---> C2H2(g)ΔH° = ??? kJ
C2H2(g) + 5⁄2O2(g) ---> 2CO2(g) + H2O(ℓ)ΔH° = −1299.5 kJ
C(s) + O2(g) ---> CO2(g)ΔH° = −393.5 kJ
H2(g) + 1⁄2O2(g) ---> H2O(ℓ)ΔH° = −285.8 kJ
+226.7 kJ
If 5.0 moles of oxygen and 3.0 moles of nitrogen are placed in 30.0 L tank at a temperature of 25 C, what will the pressure of the resulting mixture of gases be?
6.5 atm
When power was turned off to a 30.0 gal. water heater, the temperature of the water dropped from 75.0 C to 22.5 C. How much heat was lost to the surroundings in kJ? (1 gal = 3.785 L)
2.49 x 10^4 kJ
How much heat will be absorbed when 38.2 g of bromine reacts with excess H2 according to the following equation?
H2 + B2 -> 2HBr H=72.80 kJ
+17.4 kJ
A piece of metal weighing 59.047 g was heated to 100.0 C and then put it into 100.0 mL of water (initially at 23.7 C). The metal and water were allowed to come to an equilibrium temperature, determined to be 27.8 C. Assuming no heat is lost to the environment, calculate the specific heat of the metal.
0.402 J/g C
Find the ΔH of the following reaction: C(s, gr) + O2(g) ---> CO2(g)
SrO(s) + CO2(g) ---> SrCO3(s) ΔH = −234 kJ
2SrO(s) ---> 2Sr(s) + O2(g) ΔH = +1184 kJ
2SrCO3(s) ---> 2Sr(s) + 2C(s, gr) + 3O2(g) ΔH = +2440 kJ
ΔHf = −394 kJ
A helium balloon with an internal pressure of 1.00 atm and a volume of 4.50 L at 20.0 C is released. What volume will the balloon occupy at an altitude where the pressure is 0.600 atm and the temperature is -20.0 C?
23.0 C
14.0 g of metal at 24.0 C has 250 joules of heat added to it. The metal's specific heat is 0.105 J/g C. What is its final temperature?
Tf = 194 C
What is the specific heat of aluminum if the temperature of a 28.4 g sample of aluminum is increased by 8.1 C when 207 J of heat is added?
c = 0.90 J/g C
In a coffee-cup calorimeter, 100.0g of H2O and 100.0 mL of HCl are mixed. The HCl had an initial temperature of 44.6 C and the water was originally at 24.6 C. After the reaction, the temperature of both substances is 31.3 C. Calculate how much heat the water lost or gained.
Q water = 2.8 x10^3 J
Find the ΔHf (heat of formation) for acetic acid, HC2H3O2, using the following thermochemical data:
HC2H3O2 (l)+2O2 (g) ->2CO2 (g)+2H2O(l) ΔH=−875kJ/mole
C(s) + O2 (g)a -> CO2 (g) ΔH = − 394.51 kJ / mole
H2 (g)+ 1⁄2O2 (g) -> H2O(l) ΔH=−285.8kJ/mole
ΔH = -1628 kJ/mol
Calculate the temperature of a container with 10.76 atm pressure exerted by 1.502 mol of CO2 in a 3.50000 L. (a=3.59 atm L^2/mol^2 b= 0.0427 L/mol)
318 K
50.0 g of iron that has an initial temperature of 225 C, and 50.0 g of gold that has an initial temperature of 25.0 C, are brought into contact with one another. Assuming no heat is lost to the surroundings, what will be the temperature when the two metals reach thermal equilibrium? The specific heat capacity if iron = 0.449 J/g C and gold = 0.128 J/g C.
Tf = 181 C
The combustion of propene proceeds in two steps:
CH2CHCH3 (g) + H2 (g) -> CH3CH2CH3 (g) H = -124 kJ
CH3CH2CH3 (g) + 5O2 (g) -> 3CO2 (g) + 4 H2O (g) H= -2220 kJ
Calculate the value of delta H for the combustion of 2.70 mol of propene into carbon dioxide and water.
-6328.8 kJ
A 500-mL bottle of water at room temperature and a 2-L bottle of water at the same temperature were placed in a refrigerator. After 30 minutes, the 500-mL bottle of water had cooled to the temperature of the refrigerator. An hour later, the 2-L of water had cooled to the same temperature. When asked which sample of water lost the most heat, Student A replied that both bottles lost the same amount of heat because they started at the same temperature and finished at the same temperature. Student B thought that the 2-L bottle of water lost more heat because there was more water. A third student believed that the 500-mL bottle of water lost more heat because it cooled more quickly. A fourth student thought that it was not possible to tell because we do not know the initial temperature and the final temperature of the water. Indicate which of these answers is correct and describe the error in each of the other answers.
Student A is incorrect because the mass of water in both containers is not the same.
Student C is incorrect because the bottle cooled quicker due to less mass of water.
Student D is incorrect because it doesn't matter what the change in temperature is as long as it is the same for both bottles.
Student B is correct: if the change in temperature is the same, the one with the more mass (the 2L bottle) had more heat loss.
Calculate delta H for the following reaction:
C2H6 + O2 ---> 3H2 + 2CO
2C2H6 + 7O2 ---> 4CO2 + 6H2O ΔH = −3119.7 kJ
2H2 + O2 ---> 2H2O ΔH = −478.84 kJ
2CO + O2 ---> 2CO2 ΔH = −565.98 kJ
-275.61 kJ
Two flasks are connected with a stopcock, Flask #1 has a volume of 2.5 L and contains oxygen gas at a pressure of 0.70 atm. Flask #2 has a volume of 3.8 L and contains hydrogen gas at a pressure of 1.25 atm. When the stopcock between the two flasks is opened and the gases are allowed to mix, what will the resulting pressure of the gas mixture be?
1.0 atm
A 10.0 g sample of a metal at 78.0 C is submerged in 50.0 mL of water at 25.0 C. The final temperature of the water is measured to be 26.1 C. Assuming no heat is lost to the surroundings, what is the specific heat of the metal?
.44 J/g C
Many cigarette lighters contain liquid butane, C4H10. Using the heat of formation, calculate the quantity of heat produced for gaseous butane is completely combusted in air. (butane: ΔHf = −126 kJ/mol, water = -242 kJ/mol, CO2 = -394 kJ/mol, O2 = 0 kJ/mol)
ΔH = −5320 kJ
One method of generating electricity is by burning coal to heat water, which produces steam that drives an electric generator. To determine the rate at which coal is to be fed into the burner in this type of plant, the heat of combustion per ton of coal must be determined using a bomb calorimeter. When 1.00 g of coal is burned in a bomb calorimeter, the temperature increases by 1.48 °C. If the heat capacity of the calorimeter is 21.6 kJ/°C, determine the heat produced by combustion of a ton of coal (2000 pounds). Remember 1 kg = 2.2 pounds
2.91 x 10^7 kJ
Calculate ∆H for the reaction
CH4 (g) + NH3 (g) → HCN (g) + 3 H2 (g),
given:
N2 (g) +3H2 (g) →2NH3 (g) ∆H=‐91.8kJ
C(s) +2H2 (g) →CH4 (g) ∆H=‐74.9kJ
H2 (g) +2C(s) +N2 (g) →2HCN(g) ∆H=+270.3kJ
256 kJ