Energetics test

What is the reading on the thermometer?

• 28.3

• 28.6

• 29.2

• 28.5

A student adds a small amount of ammonium chloride to a beaker of water. The temperature of the water decreases. What type of reaction has occurred and why?

• Exothermic as heat is released to the surroundings.

• Exothermic as heat is absorbed from the surroundings.

• Endothermic as heat is released to the surroundings.

• Endothermic as heat is absorbed from the surroundings.

From the energy level diagram, what is the type of reaction and corresponding energy change?

• Endothermic as heat is released.

• Endothermic as heat is absorbed.

• Exothermic as heat is released.

• Exothermic as heat is absorbed.

Which statement about this reaction is NOT correct?

• The temperature of the surroundings increases.

• The reaction is endothermic.

• The products have less energy than the reactants.

• Energy is released during the reaction.

In the energy profile diagram shown

• 2 is the energy absorbed and 3 is the products.

• 2 is the energy released and 3 is the products.

• 2 is the energy absorbed and 3 is the reactants.

• 2 is the energy released and 3 is the reactants.

Which one is the correctly labelled diagram for an endothermic reaction?

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• 
• 
• 

When 3g of Magnesium is added to 100cm3 of copper sulphate solution, the temperature increases by 35°C.

Calculate the heat energy change (Q) in kJ.

[for the solution, 1.0 cm3 has a mass of 1.0g and c = 4.2J/g/°C]

• -14.7 KJ

• +14.7 KJ

• -14,700 KJ

• +14,700 KJ

What is meant by the term exothermic?

• A reaction that takes in heat energy from the surroundings, resulting in a temperature decrease. of the surroundings.

• A reaction that releases heat energy to the surroundings, resulting in a temperature increase. of the surroundings.

• A reaction that takes in heat energy from the surroundings, resulting in a temperature increase. of the surroundings,

• A reaction that releases heat energy to the surroundings, resulting in a temperature decrease of the surroundings.

When measuring the enthalpy of combustion of a fuel what measurements must be taken?

Choose all correct answers.

• Mass of burner at the start.

• Volume of water being heated.

• Mass of burner after burning.

• Temperature of water at the start.

• Temperature of the water after being heated.

When measuring the enthalpy of combustion of a fuel, what are the biggest sources of error?

Choose 2.

• Heat loss to surroundings.

• Incorrect reading of the thermometer.

• Incomplete combustion of the fuel.

• Incorrect reading of mass from balance.