EduNinja
[Maximum number: 1]

The energy level diagram for the reaction between X2X_{2} and Y2Y_{2} to form XY gas is shown.

Question image

Which statement is correct?

A

Energy is released when X2X_{2} and Y2Y_{2} bonds are broken.

B

Energy is needed to form XY bonds.

C

The energy change, ΔH\Delta H, for the reaction is negative.

D

The reaction is endothermic.

[Maximum number: 1]

Methane burns in oxygen to form carbon dioxide and water.

CH4+2O2→CO2+2H2O\mathrm{CH}_{4}+2 \mathrm{O}_{2} \rightarrow \mathrm{CO}_{2}+2 \mathrm{H}_{2} \mathrm{O}

The bond energies are shown in the table.

Table

What is the energy change for the reaction?

A

−818 kJ/mol-818 \mathrm{~kJ} / \mathrm{mol}

B

−323 kJ/mol-323 \mathrm{~kJ} / \mathrm{mol}

C

+323 kJ/mol+323 \mathrm{~kJ} / \mathrm{mol}

D

+818 kJ/mol+818 \mathrm{~kJ} / \mathrm{mol}

[Maximum number: 1]

Statement 1 Hydrogen is used as a fuel.
Statement 2 When hydrogen burns in the air to form water, heat energy is produced.
Which is correct?

A

Both statements are correct and statement 2 explains statement 1.

B

Both statements are correct but statement 2 does not explain statement 1.

C

Statement 1 is correct but statement 2 is incorrect.

D

Statement 2 is correct but statement 1 is incorrect.

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