What do you understand by exothermic reaction and endothermic reaction? Give one example of each type.

The enthalpy change for the reaction $2CO_{(g)} + O_{2(g)} \rightarrow 2CO_{2(g)}$ is known as:

The bond energies of $H-H$ and $Cl-Cl$ are $430 \ kJ \ mol^{-1}$ and $240 \ kJ \ mol^{-1}$ respectively. If the $\Delta H_f$ (enthalpy of formation) of $HCl$ is $-90 \ kJ \ mol^{-1}$,what is the $H-Cl$ bond energy in $kJ \ mol^{-1}$?

Equal volumes of $1 \, M \, HCl$ and $1 \, M \, H_2SO_4$ are neutralized by a dilute $NaOH$ solution,and $x$ and $y \, kcal$ of heat are liberated,respectively. Which of the following is correct?

Fill in the blanks:
$(i)$ The enthalpy change that occurs when one mole of a compound is formed from its constituent elements in their standard states is called the ...... of that compound.
$(ii)$ The total heat change in a chemical reaction is equal to the algebraic sum of the heat changes of the individual steps of the reaction. This law was given by ............. .
$(iii)$ $A$ process during which there is no exchange of heat between the system and the surroundings is called an ................ process.
$(iv)$ The standard enthalpy value of any element in its standard state is considered to be ...... .

The enthalpy of solution of $NaOH$ (solid) in water is $-41.6 \ kJ \ mol^{-1}$. When $NaOH$ is dissolved in water,the temperature of the water