Question

What kind of chemical reaction is :
$2Cu + {O_2}{\text{ }} \to {\text{ }}2CuO{\text{ + 315kJ}}$

Answer 1

When copper reacts with oxygen then it forms copper oxide. It represents that two elements combine and from a product. Thus we can classify it as a combination reaction also. Also when the above reaction takes place some amount of energy is also released. Hence we will classify reactions on the basis of transfer of energy also.

Complete Step By Step Answer:
We are given with the reaction as:
$2Cu + {O_2}{\text{ }} \to {\text{ }}2CuO{\text{ + 315kJ}}$
It can be seen that when copper reacts with oxygen molecules it forms an oxide which is known as copper oxide. We can also say that copper combines with oxygen to form a product known as copper oxide. Thus the reaction can be classified as combination reaction whose general representation is :
$A + B{\text{ }} \to {\text{ C}}$
Therefore it is one of the combination reactions. Also we can see that when copper combines with oxygen to form copper oxide then an amount of energy is released. This is known as enthalpy of the reaction. Since it is written on the product side, it is positive energy which means that during the reaction the energy is released. Therefore it is an exothermic reaction. Exothermic reactions are those in which the heat energy is released during the reaction. Thus we can say that it is a combination and exothermic reaction.

Note:
Like exothermic reactions we have endothermic reactions in which a amount of heat energy is consumed while during the reaction. Endothermic reaction is opposite to that of exothermic reaction. The value of enthalpy of reaction for endothermic reaction is negative while for exothermic reaction it is positive quantity.