Question

Are the following processes exothermic or endothermic? a. When solid \(\mathrm{KBr}\) is dissolved in water, the solution gets colder. b. Natural gas \(\left(\mathrm{CH}_{4}\right)\) is burned in a furnace. c. When concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) is added to water, the solution gets very hot. d. Water is boiled in a teakettle.

Short answer

a. Endothermic b. Exothermic c. Exothermic d. Endothermic

Step-by-step solution

a. Solid KBr is dissolved in water#{tag_content}#The solution gets colder when solid \(\mathrm{KBr}\) is dissolved in water. A process that causes the surrounding environment to become colder is likely absorbing heat, which indicates that this is an endothermic process.

b. Natural gas is burned in a furnace#{tag_content}#Burning natural gas, or \(\mathrm{CH}_{4}\), in a furnace is a combustion reaction. Combustion reactions involve combining a fuel source with oxygen and releasing energy in the form of heat and light. Since the reaction releases heat, it is an exothermic process.

c. Concentrated H2SO4 is added to water#{tag_content}#When concentrated sulfuric acid, \(\mathrm{H}_{2} \mathrm{SO}_{4}\), is added to water, the solution gets very hot. This indicates that heat is being released during this process. Since heat is being released, it is an exothermic process.

d. Water is boiled in a teakettle#{tag_content}#Boiling water involves adding energy in the form of heat to increase the temperature of the water until it reaches its boiling point and turns into steam. Since the process requires an input of energy in the form of heat, it is an endothermic process.