Endothermic and Exothermic Reactions Practical

Working and Solutions

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1. Mg(g) + 2HCl(aq) MgCl2(aq) + H2(g)

2. q (or ∆H) = mcΔT = (25+0.1)x4.18xΔT 3. n(Mg) = 0.1/24.31 = 4.11x10-3 moles4. q (per mole)= (25+0.1)x4.18xΔT n

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6. Ba(OH)2(s) + 2NH4NO3(s) Ba(NO3)2(aq) + 2NH3 (aq) + H2O(l)

7. Liquid has been formed a reaction that has increased disorder (more energy). Solid and Solid going to liquid.

8. Ammonia gas produced. Turns red litmus paper blue.

9. Enthalpy of products is more than the enthalpy of reactants.

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11. 1st reaction NaCO3(s) Na2O(s) + CO2(l)

(Endothermic – thermal decomposition)

2nd reaction Na2O(s) + H2O(l) 2NaOH(aq)

(Exothermic)

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13. Zn(s) + CuSO4(aq) ZnSO4(aq) + Cu(s)

14. q (or ∆H) = mcΔT = (25+0.1)x4.18xΔT 15. c(CuSO4) = n/v

n(CuSO4) = c x v = 0.5 moldm-3 x 0.05dm3 = 0.025 moles CuSO4

n(zinc) = 3/65.37 = 0.046 moles Zn excess16. q (per mole)= (50+3)x4.18xΔT 0.025