Problem #1 68.4 g of water is heated from 24.03 o C to 36.79 o C at constant pressure. Calculate the change in enthalpy (∆H) in Joules fo...
Problem #1
68.4 g of water is heated from 24.03 oC to 36.79 oC at constant pressure. Calculate the change in enthalpy (∆H) in Joules for this process. Consider the specific heat capacity of the water is 4.184 J/g oC.
Problem #2 When 1.18 g of NaOH is dissolved in 100.0 g of water, the temperature of the solution increases from 25.00 oC to 27.06 oC. Calculate the amount of heat absorbed (in J) by the water. The specific heat capacity of the water is 4.18 J/g oC.
Problem #3 Determine the specific heat capacity (in J/g K) of a 1.00 g sample that is heated from 18 K to 82 K using 7001 J of heat.
Problem #4 10.0 g of water is heated from 25 oC to 71.7 oC at constant pressure. Calculate the change in enthalpy. Consider the specific heat capacity of the water is 4.184 J/g K.
Problem #5 If 163.4 g of steam releases 1.15 KJ of heat per gram of steam in a room containing 55,651.97 g of air originally at 20 ˚C. What is the final temperature of the air in the room? Give the temperature in ˚C.
Problem #6 4,830 g of a metal with specific heat capacity of 1.024 J/ g oC at 40.0 oC is added to 258 g water (specific heat capacity 4.184 J/g oC) originally at 20.0 oC. What is the final temperature of the mixture?
Problem #7 100 g of a piece of iron metal with temperature of 95 ˚C was introduced to a container having 200 g of water at 25 ˚C.What would be the final temperature of the water?
(iron specific heat = 0.45 J/g ˚C) (water specific heat = 4.184 J/g ˚C)
Problem #8 Determine the ∆Ho for the reaction: P4 (g) + 10 Cl2 (g) → 4 PCl5 (s)
Given:
PCl5 (g) → PCl3 (g) + Cl2 (g) ∆Ho = 157 KJ
P4 (g) + 6Cl2 → 4PCl3 (g) ∆Ho = -1207 KJ
Problem #9 Determine the mass of oxygen gas required to produce -1278.5 KJ of heat for the reaction:
CS2 + 3O2 (g) → CO2 + 2SO2 ∆H = -1077 KJ
Problem #10 Calculate the heat released (in KJ) when 0.59 g of hydrogen gas burns according the reaction:
O2 + 2H2 → 2H2O ∆H = -484 KJ
Problem #11 How much heat is released by burning 27.5 g of CH4?
CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g) ∆H = -890.4 KJ
Problem #12 Give the chemical equation: N2 (g) + 3H2 (g) → 2NH3 (g) ∆H = -92.6 KJ
How many grams of nitrogen gas are needed to make -550 KJ of heat?
Problem #13
Calculate the mass of H2O (l) that can be converted to vapor by absorbing 4,688 KJ of heat according to the chemical process: H2O (l) → H2O (l) ∆H = 40.7 KJ at 373 K
Problem #14 When 1.55 g of hexane (C6H14) undergoes combustion in a bomb calorimeter, the temperature rises from 25.87 ˚C to 38.13 ˚C. Find the heat of the reaction (∆H) in KJ/mol hexane. The heat capacity of the bomb calorimeter (Ccal) is 5.73 KJ/˚C.
Problem #15 Magnesium metal reacts with hydrochloric acid according to the equation:
Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
In a constant pressure calorimeter, 0.158 g of Mg is combined with enough HCl to make a 100 mL solution, which has a density of 1.00 g/mL and a specific heat capacity of 4.18 J/g. The HCl is sufficiently concentrated to react with all the Mg. The temperature of the solution rises from 25.6 ˚C to 32.8 ˚C as a result of the reaction. Find the ∆H for the reaction in J/mol Mg.
Problem #16 In a bomb calorimeter, 2.6 g of CaCl2 (s) is dissolved in 260 g water at 23 oC. If the temperature increases to 26.4 oC, what is the enthalpy change for this process?
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