C3.3

Question 1

What is the definition of a mol?

Answer 1

The mass of the substance divided by the RFM

Question 2

1 gram has the same mass as what?

Answer 2

1 ml

Question 3

What is the only waste product from using hydrogen as a fuel?

Answer 3

Water

Question 4

What do catalysts do in a reaction?

Answer 4

Provide a different pathway for a chemical reaction that has a lower activation energy

Question 5

What happens in an exothermic reaction regarding energy?

Answer 5

The energy released from forming new bonds is greater than the energy needed to break existing bonds

Question 6

What happens in an endothermic reaction regarding energy?

Answer 6

The energy needed to break existing bonds is greater than the energy released from forming new bonds

Question 7

What is the word equation for the combustion of hydrogen in air?

Answer 7

Hydrogen + oxygen -> water

Question 8

What are advantages and disadvantages of using hydrogen for fuel?

Answer 8

+ Less pollutants
+ Less need for fossil fuels
- Expensive
- Storing it is difficult as hydrogen is explosive

Question 9

How can hydrogen be used in cars?

Answer 9

~ Combustion engine (hydrogen is burnt, has to be stored in tanks at high pressure, may have to be liquid)
~ Fuel cells (chemical reaction produces electricity to power the car, hydrogen isn’t burnt)