Answer:
1. A combination reaction occurs when two reactants react with each other forming a product. An example of this is when hydrogen gas and oxygen gas react, forming water. On the other hand, a decomposition reaction is a type of reaction wherein a reactant decomposes into two different components. An example of this is when water is electrolyzed, forming hydrogen gas and oxygen gas as products.
2. Temperature affects the rate of reaction as it increases the average kinetic energy of the molecules. With this, the molecules will have more energy for the reaction, thus, affecting the rate. The concentration of reactants also affect the rate of reaction since there are more molecules present, thus more collisions of reactans, therefore increasing the rate of reaction.