Year 12 ICAS Science 5-Question Sample

Question 1 of 5 Natural and processed materials

A catalyst lowers the activation energy of a reversible reaction from 70 to 39 units. Only 5 g of catalyst was added to a 30 kg batch, and all 5 g were recovered afterwards. How can so little convert so much?

Weighed before and after the batch

What was weighed	Before the run	After the run
Catalyst	5 g	5 g recovered
Reactant	30 kg	mostly converted to product
Barrier crossed	70 units	39 units

A The catalyst is extremely concentrated, so 5 g carries the work of many kilograms B Each catalyst particle is released unchanged and goes straight on to the next molecule C The catalyst is used up slowly, so 5 g lasts just long enough for 30 kg D The catalyst lowers the energy of the reactants themselves, so they react without help

Question 2 of 5 Energy and change

Two identical brake lamps on a trailer run from a 24 V supply, wired one way in the first setup and the other way in the second. A voltmeter placed across ONE lamp reads 12 V. Which setup is being measured, and what would the other have read?

The two wiring setups

Setup	Paths from the supply	Voltage across each lamp
First	one, running through both lamps	12 V
Second	two, one for each lamp	24 V

A The second setup, since one loop splits 24 V evenly and the first would have read 24 V B The first setup, since one loop splits 24 V evenly and the second would have read 24 V C The first setup, since a lamp always drops half of whatever it is given D The second setup, since the two branches divide the supply between them

Question 3 of 5 Observing and measuring

A diver looking up through calm water watches a heron flying about 1.2 m above the surface. The bird appears HIGHER in the sky than that. Where should the diver judge it to be?

A Higher than it looks, since the ray bends away from the vertical as it enters the water B Exactly where it looks, since the diver is looking straight up at it C Lower than it looks, since the ray bends toward the vertical as it enters the water D Lower than it looks, since the water surface acts as a mirror at that angle

Question 4 of 5 Investigating

A company makes the four claims in the panel about a seed coating. An investigator has an independent survey of 350 growers who have used the product, and no plots of their own. Which claim could that evidence show to be FALSE?

The four claims as written

For each claim, name a figure this evidence could produce that would defeat it.

Treated plots will out yield untreated plots by at least 7 per cent
Soil organic carbon will rise by at least 0.4 percentage points over five years
At least 80 per cent of growers who try it rate it good or better
The product feeds the crop in a more natural way

A The yield claim, since growers can be asked what their paddocks did B The soil carbon claim, since 350 properties cover a great deal of soil C The natural feeding claim, since growers can say whether it feels natural D The satisfaction claim, since the survey could return under 80 per cent

Question 5 of 5 Natural and processed materials

A 200 mL mixture of ethanol and water has to be parted into its two components. Which difference in the table makes that possible, and which method does the table rule out?

The two components compared

Component	Boiling point	Density	Mixes with the other
Ethanol	78 degrees Celsius	0.79 g per mL	completely
Water	100 degrees Celsius	1.00 g per mL	completely

A The densities differ, so the lighter liquid can be poured off the top B The boiling points differ by 22 degrees, and mixing completely is what rules out settling C One dissolves and the other does not, so a filter will part them D The boiling points differ by 22 degrees, and the densities are what rule out settling

Year 12 Science sample

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