Chemistry Quiz 1 (Year 9) U4 9Fa

He adds ammonium nitrate to the water, and stirs until it dissolves.

a)

The water between the flask and the wooden block freezes. Explain why.

b)

Does ammonium nitrate dissolve exothermically or endothermically? Explain how you know.

b)

Explain how the data show that the neutralisation reaction is exothermic.

Josie investigates four fuels. She sets up the apparatus below. She uses the fuels to heat water.

She measures the temperature change of the water when she burns different fuels in the spirit burner.

a)

Identify the variable Josie changes

Josie investigates four fuels. She sets up the apparatus below. She uses the fuels to heat water.

She measures the temperature change of the water when she burns different fuels in the spirit burner.

b)

Identify the variable Josie measures

c)

Josie heats the same volume of water with each fuel. Name two other variables that Josie should control.

d)

Josie does some preliminary work to help her decide what volume of water to heat with the fuels. Suggest why.

e)

Josie’s results are in the table.

What are the missing values for propanol and butanol in the table?

f)

Which fuel released least energy on burning?

g)

Josie decided to repeat her investigation. Suggest why.

h)

Josie thinks that some of the heat released by the burning fuels was not transferred to the water. Where else might the heat have been transferred to?