Y10 C6 Energy Changes in Chemistry

Which the main type of energy stored in the bonds between atoms, ions and molecules?

• Chemical

• Kinetic

• Magnetic

• Nuclear

When the temperature of a reaction rises this is an example of...

• an endothermic reaction.

• an exothermic reaction.

• a decomposition reaction.

• a neutralisation reaction.

The breaking of bonds between atoms, ions or molecules is an example of...

• an exothermic process.

• an endothermic process.

The formation of bonds between atoms, ions or molecules is an example of...

• an exothermic process.

• an endothermic process.

An exothermic reaction can be described as requiring...

• less energy to break the bonds in the reactants than is released when the bonds in the products are formed.

• more energy to break the bonds in the reactants than is released when the bonds in the products are formed.

• the same amount of energy to break bonds as the energy released when new bonds are formed.

In an endothermic reaction the...

• reactants contain less energy than the products.

• reactants contain more energy than the products.

The energy level diagram shown is for an

• exothermic reaction.

• endothermic reaction.

The energy level diagram shown is for an...

• exothermic reaction.

• endothermic reaction.

Which calculation could be used to correctly determine the energy change of the following reaction?

3H_2(g) + N_2(g) ⇌ 2NH_3(g)

• (6 × 391) − [(3 × 436) + 945]

• (3 × 391) − (436 + 945)

• [(3 × 436) + 945] − (3 × 391)

• [(3 × 436) + 945] − (6 × 391)

When methane undergoes incomplete combustion carbon monoxide and water are produced.

2CH_4(g) + 3O_2(g) → 2CO_(g) + 4H₂O_(g)

The energy change can be calculated using which of the following sums?

• [2(1077) + 4(463)] − [2(414) + 3(498)]

• [2(414) + 3(498)] − [2(1077) + 4(463)]

• [8(414) + 3(498)] − [2(1077) + 8(463)]

• [2(1077) + 8(463)] − [8(414) + 3(498)]