Is the reduction of copper from copper (ii) oxide by carbon exothermic or endothermic? what is the sign of the energy change?

Answer;

-Exothermic reaction;

-The sign of the energy change is negative (-)

Explanation;

2CuO (s) + C (s) - -> 2Cu (s) + CO2 (g)

ΔH = ΣΔHf (products) - ΣΔHf (reactants)

ΔH = - 393.5kJ - 2 (-155.2kJ) = - 83.1 kJ

The reaction is exothermic.

-An exothermic process or reaction releases heat, causing the temperature of the immediate surroundings to rise. An endothermic process absorbs heat and cools the surroundings.