Chapter 6: Thermal Equilibrium, Enthalpy, Calorimetry, and Hess's Law
How much energy is required to heat up 80 g of water from 26C to 48C? Give your answer in J.
7.4 x 103 J
To what volume should you dilute 50.0mL of a 12M stock HNO3 solution to obtain a 0.100 M HNO3 solution
6.0L or 6.0 x 103mL
If a gas at 25.0 °C occupies 3.60 liters at a pressure of 1.00 atm, what will be its volume at a pressure of 2.50 atm?
Determine the limiting reagent of the following reaction, assuming you react 1.20 mol Al and 2.40 mol I2:
2Al + 3I2 --> 2AlI3
Limiting reagent = Aluminum
If 16 J of work is being done on a system and 1016 J of heat are being gained by the surroundings, what is the total energy change of the system?
-1000J
A silver block, initially at 58.5C, is submerged into 100.0 g of water at 24.8C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 26.2C. What is the mass of the silver block? Specific heat capacity for silver is 0.235 J/gC and for water is 4.18 J/gC.
77.1 g Ag
What mass (in grams) of Mg(NO3)2 is present in 145 mL of a 0.150 M solution of Mg(NO3)2?
3.23g Mg(NO3)2
600.0 mL of air is at 20.0 °C. What is the volume at 60.0 °C?
According to Charle's Law, 682 mL
What mass of Al2O3 can be produced from the reaction of 10.0 g of Al and 19.0 g of O3 according to the following balanced equation:
2Al + O3 --> Al2O3
Theoretical Yield = 18.9 g Al2O3
How much heat (in J) is required to warm 1.50 L of water from 25.0 C to 100.0 C? (Assume a density of 1.0 g/mL for the water). Specific heat capacity of water is 4.18J/gC.
4.70 x 105 J
Consider the following reaction: 2C4H10 + 13O2 → 8CO2 + 10H2O ΔHrxn = -2044 kJ If we have a 10.8 kg sample of C4H10, calculate heat in kJ for the complete combustion of all C4H10 present.
-1.90 x 105 kJ
What volume of 0.0995 M Al(NO3)3 will react with 3.66 g of Ag according to the following chemical equation?
3 Ag(s) + Al(NO3)3(aq)→3 AgNO3(aq) + Al(s)
0.114 L Al(NO3)3
A flexible container at an initial volume of 5.120 L contains 8.500 mol of gas. More gas is then added to the container until it reaches a final volume of 18.10 L. Assuming the pressure and temperature of the gas remain constant, calculate the number of moles of gas added to the container.
21.55 moles added
Upon reaction of 1.274 g of copper sulfate with excess zinc metal, 0.392 g copper metal was obtained according to the equation:
CuSO4(aq)+Zn(s)→Cu(s)+ZnSO4(aq)
What is the percent yield?
77.3%
A sample of neon effuses from a container in 76 seconds. The same amount of an unknown noble gas requires 155 seconds. Identify the second gas.
Krypton
Find the enthalpy change for this reaction,
{{ 2S + 3O2 → 2SO3 }}
using the enthalpies of other reactions given:
S + O2→ SO2 ∆H = - 297 kJ
2SO3 → 2SO2 + O2 ∆H = 198 kJ
-792kJ
H3PO4 + 3 NaOH --> Na3PO4 + 3 H2O
If 36.0 mL of H3PO4 react exactly with 80.0 mL of 0.500 M NaOH, what is the concentration of the phosphoric acid?
0.370 M
96.0 g of a gas occupies 48.0 L at 700.0 mm Hg and 20.0 °C. What is its molecular weight?
52.2 g/mol
A 2.00 g sample of ammonia reacts with 4.00 g of oxygen according to the equation
4NH3+5O2→4NO+6H2O
How much excess reactant (in grams) remains after the reaction has stopped?
0.297g excess NH3 remains
A piston has external pressure of 8.80 atm. How much work has been done if the cylinder goes from volume of 0.550 L to 0.950 L? (101.3 J = 1L*atm). Give your answer in J.
-357 J
When 0.514 g of biphenyl (C12H10) undergoes combustion in a bomb calorimeter, the temperature rises from 25.8C to 29.4C. Find ΔErxn for the combustion of biphenyl in kJ/mol biphenyl. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.86 kJ/C.
ΔErxn = -6.33 x 103 kJ/mol
Consider the following balanced precipitation reaction:
2Na3PO4(aq) + 3CuCl2(aq) --> Cu3(PO4)2(s) + 6NaCl
Determine what volume of 0.175 M Na3PO4 solution is necessary to completely react with 95.4mL of 0.102 M CuCl2?
0.0371L
500.0 liters of a gas in a flexible-walled container are prepared at 700.0 mmHg and 200.0 °C. The gas is placed into a tank under high pressure. When the tank cools to 20.0 °C, the pressure of the gas is 30.0 atm. What is the volume of the gas?
According to the Combined Gas Law, 9.51 L
Calculate the root mean square velocity of I2(g) at 373K.
191m/s