Unit 8: Exothermic and Endothermic Reactions

What is an exothermic reaction?

• A reaction that absorbs energy from the surroundings

• A reaction that releases energy to the surroundings

• A reaction that requires oxygen to occur

• A reaction that produces water as a waste product

Which of the following is an example of an exothermic reaction?

• Baking soda and citric acid reaction

• Ice melting

• Potassium + water → potassium hydroxide + hydrogen

• Sodium + water → sodium hydroxide + hydrogen

What are the requirements for combustion?

• Fuel, oxygen, and heat

• Fuel, water, and heat

• Fuel, carbon dioxide, and heat

• Fuel, nitrogen, and heat

Which of the following is an example of an endothermic process?

• Dissolving potassium chloride in water

• Burning of coal

• Rocket engines

• Rusting of iron

What is the general word equation for reactions of metals with oxygen?

• metal + oxygen → metal oxide

• metal + water → metal hydroxide + hydrogen

• metal + acid → salt + hydrogen

• metal + steam → metal oxide + hydrogen

Which metal does not react with oxygen or acids?

• Gold

• Iron

• Sodium

• Magnesium

What is the waste product produced when hydrogen burns in rocket engines?

• Carbon dioxide

• Water

• Oxygen

• Hydrogen peroxide

What is the product of the reaction between magnesium and hydrochloric acid?

• Magnesium chloride + hydrogen gas

• Sodium citrate + water + carbon dioxide

• Potassium hydroxide + hydrogen

• Metal oxide + hydrogen

What is the product of the reaction between carbon and oxygen?

• Carbon dioxide

• Water

• Oxygen

• Hydrogen peroxide

What is the product of the reaction between sodium and water?

• Sodium hydroxide + hydrogen

• Sodium chloride + hydrogen

• Sodium citrate + water + carbon dioxide

• Sodium oxide + hydrogen