SACE Stage 2 Chemistry topics 1 to 4: exam-style practice quiz

It splits $\text{NO}_2$ into NO and oxygen atoms, which react with $\text{O}_2$ to form ozone

It combines nitrogen and oxygen directly into $\text{NO}_2$ at ground level on hot days

It breaks ozone down into oxygen molecules, which removes the smog from the lower air

It converts carbon dioxide into carbon monoxide inside the engines of motor vehicles

Carbon dioxide reacts directly with shells to form more solid calcium carbonate on reefs

Carbonate ion concentration rises, because carbon dioxide itself contains carbon atoms

Carbonate ions are unaffected, because only the pH of the surrounding seawater changes

Hydrogen ions from carbonic acid react with carbonate ions, lowering their concentration

The least polar component

The most polar component

The component with the smallest molar mass

The component present in the greatest amount

Every element absorbs all wavelengths of light, but each one absorbs them at a different speed

The sample is weighed before and after absorbing light to find the mass of each element

Each element's electrons have unique energy levels, so it absorbs its own characteristic wavelengths

Each element emits a different colour of light when it is dissolved in water at room temperature

$1s^2\,2s^2\,2p^6\,3s^2\,3p^4$

$1s^2\,2s^2\,2p^6\,3s^2\,3p^6$

$1s^2\,2s^2\,2p^6\,3s^2\,3d^4$

$1s^2\,2s^2\,2p^8\,3s^2\,3p^2$

The activation energy of the reaction increases as the reaction proceeds

The product acts as a catalyst that gradually slows the reaction down

The temperature of the reaction mixture must be rising steadily over time

Reactant concentration decreases, so successful collisions become less frequent

A low temperature would give a higher yield but a rate too slow to be economic

A low temperature would give a lower yield and also a slower rate of reaction

A moderate temperature gives the highest possible yield of ammonia at equilibrium

The iron catalyst works only at temperatures above the boiling point of ammonia

Propanone turns the solution from orange to green; propanal leaves it orange

Propanal turns the solution from orange to green; propanone leaves it orange

Both turn the solution from orange to green, since both contain a C=O group

Neither changes the colour, since neither compound contains an OH group

fermentation, producing ethanol and carbon dioxide

addition polymerisation, producing a long-chain polymer

transesterification, producing methyl esters and glycerol

hydrolysis, producing fatty acids and water only

It adds $\text{Ca}^{2+}$ and $\text{Mg}^{2+}$ ions to the water so that soaps become more effective

It forces the water through a semi-permeable membrane under a high applied pressure

It clumps suspended clay particles together so that they settle out of the water

It swaps $\text{Ca}^{2+}$ and $\text{Mg}^{2+}$ in the water for $\text{Na}^+$ held on the zeolite

$\text{H}^+$ displaces nutrient cations such as $\text{K}^+$ from silicate surfaces, so they leach away

$\text{H}^+$ ions bond to nitrogen gas from the air and so remove the nitrogen from the soil

Acidic water adds extra $\text{K}^+$ and $\text{Ca}^{2+}$ ions to the surfaces of the silicates

Acidity has no effect on cations in the soil, only on the anions that the soil holds

Thermosets soften on heating and can be remoulded; thermoplastics are cross-linked and do not melt

Thermoplastics are made from renewable materials, while thermosets come from fossil resources only

Thermoplastics soften on heating and can be remoulded; thermosets are cross-linked and do not melt

Thermosets are biodegradable, so they break down before they can ever be collected for recycling

Sodium forms at the positive anode and chlorine gas forms at the negative cathode

Sodium forms at the negative cathode and chlorine gas forms at the positive anode

Hydrogen gas forms at the cathode and oxygen gas forms at the anode

Sodium forms at the negative anode and chlorine gas forms at the positive cathode