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Higher Chemistry. Unit 3 Section 2 Hess’s Law Multiple Choice Questions. This is designed to be used by teachers to help students develop skills in answering multiple choice questions. Douglas Racey, Waid Academy, Anstruther, Fife, Scotland.
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Higher Chemistry Unit 3Section 2 Hess’s LawMultiple Choice Questions This is designed to be used by teachers to help students develop skills in answering multiple choice questions. Douglas Racey, Waid Academy, Anstruther, Fife, Scotland
Higher Chemistry Unit 3 - Section 2 Hess’s LawMultiple Choice Questions 1. What is the relationship between enthalpies p, q, r and s? S(s) + H2(g) H2S(g) DH=p H2(g) + ½ O2(g) H2O(l) DH=q S(s) + O2(g) SO2(g) DH=r H2S(g) + 1½ O2(g) H2O(l) + SO2(g) DH=s A. p = q + r – s B. p = s – q – r C. p = q – r – s D. p = s + r – q A. Answer
Higher Chemistry Unit 3 - Section 2 Hess’s LawMultiple Choice Questions 2. The enthalpies of combustion of C(s), H2(g) and C4H9OH(l) (in kJmol-1) are as follows C(s) + O2(g) CO2(g) DH=a H2(g) + ½O2(g) H2O(l) DH=b C4H9OH(l) + 6O2(g) 4CO2(g) + 5H2O(l) DH=c What is the enthalpy change for the reaction shown below? 4C(g) + 5H2(l) + ½O2(g) C4H9OH(l) A. c – 4a – 5b B. 2a + 10b - c C. 4a + 5b - c D. 2a + 5b + c C. Answer
Higher Chemistry Unit 3 - Section 2 Hess’s LawMultiple Choice Questions 3. Consider the reaction pathway shown. DH = -210 kJmol-1 W Z D= -50 kJmol-1 DH = -86kJmol-1 X Y According to Hess’ Law, the DH value, in kJmol-1 for reaction Z to Y is A. +74 B. -74 C. +346 D.-346 C. Answer