So, we need to break the bonds of liquid substance in order to convert it into vapor state. And, energy is absorbed for breaking of bonds which means that evaporation is an endothermic process.

Hence, the statement evaporation of water is an exothermic process is false.

When a hydrocarbon reacts with oxygen and leads to the formation of carbon dioxide and water then this type of reaction is known as combustion reaction.

A combustion reaction will always release heat energy. Hence, combustion reaction is exothermic in nature.

When energy is transferred as heat from the surroundings to the system then it means energy is being absorbed by the system. And, absorption of heat is an endothermic process for which $\Delta H$ is positive.

Whereas when energy is transferred from system to the surrounding then it means energy is released by the system which is an exothermic process.

Hence, for an exothermic process value of $\Delta H$ is negative.

Thus, we can conclude that statements which are true are as follows.

A combustion reaction is exothermic.

When energy is transferred as heat from the system to the surroundings, $\Delta H$ is negative.

For an endothermic reaction Deta H is positive.

5 0

3 years ago

To determine the limiting reactant in a chemical reaction, one must know the:.

sveticcg [70]

Answer:

The available amounts of each reactant

Explanation:

The limiting reactant is the reactant that will limit the equation.

For example, I have 2N2 and H2O. In this situation, H2O would be the limiting reactant since there is only one atom, while N2 has two atoms.

Think of it like you're making peanut butter and jelly. You have 50 cans of peanut butter and only 10 jelly. Which means you can only make sandwiches using 10 jars of jelly and 10 jars of peanut butter.

4 0

2 years ago