G9 Chemistry (S2M1)

Identify this process.

Combustion

• Endothermic

• Exothermic

Identify this process.

Neutralisation

• Endothermic

• Exothermic

Identify this process.

Evaporation

• Endothermic

• Exothermic

Identify this process.

Melting

• Endothermic

• Exothermic

Identify this process.

Freezing

• Endothermic

• Exothermic

The table below gives the temperature changes when different substances dissolve in water. The same mass of solid was used in each test and the same volume of water.

Identify the substance that releases (give out) heat the most.

• copper sulfate

• ammonium chloride

• ammonium nitrate

• potassium nitrate

Mr. Mushi sets up the apparatus below.

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

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

• because the wooden block absorbed the heat from the water in between the flask.

• because the mixture from the flask released heat to the water during the reaction

• because it was placed inside the freezer

• because the mixture from the flask absorbed the heat from the water during the reaction

Zoza investigates a neutralisation reaction. She adds 50 cm³of potassium hydroxide solution to 50 cm³ of nitric acid. Her results are in the table below.

Use data from the table to calculate the temperature change during the reaction.

• 23

• 46

• 33

• 56

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.

Identify the variable Josie measures.

• time of exposure

• temperature of water

• type of fuel

• amount of water

Ashok compares the heat released in different neutralisation reactions. He uses the apparatus below.

Ashok repeats his investigation three times. The table below summarises his results.

Which among the reactants releases heat the most.

• hydrochloric acid and potassium hydroxide

• nitric acid and sodium hydroxide

• sulfuric acid and potassium hydroxide

• sulfuric acid and sodium hydroxide