WorksheetsEnergy in Chemical Reactions
Total questions: 15
Worksheet time: 2hrs 49mins
Q1: How much energy is required to decompose 765 g of PCl3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful.
4 PCl3(g) → P4(s) + 6Cl2(g)
ΔH= +1207 kJ
2.31 × 103 kJ
5.95 × 103 kJ
4.33 × 103 kJ
1.68 × 103 kJ
Q2: Using the following equation for the combustion of octane, calculate the heat of reaction for 100.0 g of octane. The molar mass of octane is 114.33 g/mole.
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
ΔH= -11018 kJ
4.82 kJ
9.64 x 103 kJ
4.82 x 103 kJ
1.26 x 104 kJ
Q3: How many kJ of heat are consumed when 5.10 g of H2 (g) is formed according to the following reaction:
CH3OH (l) → CO (g) + 2H2 (g)
ΔH° = +128.1 kJ
653 kJ
326 kJ
62 kJ
162 kJ
Q4: How many kJ of heat are released in the combustion of 16.0 g of C6H6 ?
2C6H6 + 15O2 →12CO2 + 6H2O
ΔH° = -6535 kJ
5.23 × 104 kJ
669 kJ
2.68 × 103 kJ
1.34 × 103 kJ
Q5: According to the following thermochemical equation, what mass of HF (in g) must react in order to produce 345 kJ of energy?
SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l)
ΔH = -184 kJ
107 g
42.7 g
150. g
173 g
Q6: What volume of benzene (C6H6, d= 0.88 g/mL, molar mass = 78.11 g/mol) is required to produce 1.5 x 103 kJ of heat according to the following reaction?
2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(g)
ΔH= -6278 kJ
21 mL
75 mL
37 mL
42 mL
Q7: What mass of Cl2 must be reacted to produce 5905 kJ of energy by the following reaction?
P4 + 6Cl2 → 4PCl3
ΔH = + 2439 kJ
1030.g
171.6 g
515.0 g
300.0 g
Q8: How much energy is evolved during the reaction of 48.7 g of Al, according to the reaction below?
Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s)
ΔH° = -852 kJ
769 kJ
207 kJ
415 kJ
241 kJ
Q9: How much heat is released by the reaction of 0.95 g of S according to the following equation:
2S (s) + 3O2 (g) → 2SO3 (g)
ΔH° = -790 kJ.
12 kJ
23 kJ
790 kJ
44 kJ
Which of the following reactions would NOT be representative of this graph?
H2 (g) + O2 (g) --> H2O (l) + heat
burning gasoline
CaCO3 (s) --> CaO (s) + CO2 (g)
the reaction between Mg and HCl (aq) - (done in lab)
