Energy Changes Topic 5

What does an endothermic reaction feel like?

• It feels hotter

• It feels colder

• It produces light

• It makes a sound

What happens during an exothermic reaction?

• Energy is taken in

• Sound is produced

• Energy is given out

• Light is absorbed

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

• Melting ice

• Burning

• Electrolysis

• Dissolving salt in water

What is the energy of the products compared to the reactants in an endothermic reaction?

• Higher

• Lower

• Same

• Unpredictable

What is required to calculate the energy change for a reaction?

• Color change

• Temperature change

• Bond energies

• Sound produced

What does a negative sign in front of the energy change indicate?

• Exothermic reaction

• Endothermic reaction

• No reaction

• Reversible reaction

What is a cell in terms of chemistry?

• A single unit producing electricity

• A storage container

• A battery

• A molecule

What is the main product of a hydrogen fuel cell?

• Carbon dioxide

• Water

• Hydrogen gas

• Oxygen gas

What is the main problem with hydrogen fuel cells?

• They only work at high temperatures

• Production of hydrogen uses fossil fuels

• They produce carbon emissions

• They are too efficient

What happens at the negative electrode in a hydrogen fuel cell?

• Hydrogen gas turns into hydrogen ions

• Oxygen gas turns into water

• Hydrogen ions turn into hydrogen gas

• Water is produced directly