TCE Chemistry Level 4 (CHM415115) criteria 5 to 8: exam-style practice quiz

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It carries electrons between the two electrodes to complete the external circuit

It lets ions migrate between half-cells to keep each solution electrically neutral

It supplies the reactants that are oxidised and reduced at the two electrodes

It increases the cell potential by adding extra ions to both half-cells

Where the concentration of dissolved oxygen is lowest, deep under the water

Only at the points where the steel has been bent or put under stress

Where the concentration of dissolved oxygen is highest, near the water surface

Only where there is no water at all, on the fully dry parts of the metal

Copper

Silver

Lead

Zinc

-184 kJ

+184 kJ

+247 kJ

-431 kJ

A much larger fraction of particles have kinetic energy above the activation energy

The activation energy of the reaction is lowered as the temperature rises

The total number of particles present in the mixture increases with temperature

The enthalpy change of the reaction becomes more negative at higher temperature

$K_c = \dfrac{[\text{CaO}][\text{CO}_2]}{[\text{CaCO}_3]}$

$K_c = \dfrac{[\text{CaCO}_3]}{[\text{CaO}][\text{CO}_2]}$

$K_c = \dfrac{1}{[\text{CO}_2]}$

$K_c = [\text{CO}_2]$

The ethanoic acid has a lower pH because it contains more hydrogen atoms

The ethanoic acid has a higher pH because it is only partly ionised

Both solutions have the same pH because their concentrations are equal

The hydrochloric acid has a higher pH because it ionises completely

a ketone

a carboxylic acid

an alcohol

an ester

Radius decreases and reactivity increases

Radius increases and reactivity decreases

Radius decreases and reactivity decreases

Radius increases and reactivity increases

0.0200 mol L$^{-1}$

0.200 mol L$^{-1}$

20.0 mol L$^{-1}$

0.500 mol L$^{-1}$

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