Y7-8 Acceleration Chemistry · Free Diagnostic Mock

🎁 FREE Diagnostic

15 questions to find exactly where your chemistry is strong — and where it's not

This is a free diagnostic for the Y7-8 Acceleration Chemistry course. 15 multiple-choice questions sample all eight Stage 4 knowledge areas, from states of matter to chemical reactions.

It's an exam: answer all the questions first (you can change any answer freely), then submit the whole exam to see your report. The worked solutions and hints unlock only after you submit. Use the jump menu at the top to move around.

At the end you get a knowledge-point report: a bar for every topic you attempted, your weak spots flagged, and the exact lessons to revise.

~15 minutes. No login needed. No marks deducted for a wrong answer — never leave one blank.
Self-paced, no time limit — but try to commit to an answer before you review, just like a real test.

Year 7–8 students working at NSW Stage 4. Calculator allowed for the density question.

⭐ Q1Y7-8 Stage 4Difficulty ★States of matter › particle model

The Problem

In which state of matter are the particles packed closely in a regular, fixed pattern, only able to vibrate on the spot?

Your answer

❓ Which state is described?

A Gas
B Liquid
C Solid
D Any state above its boiling point
E A solution

🎯 Knowledge Point — what this tests

The particle model describes how closely particles are packed and how much they move in each state.

Match the two clues — "regular fixed pattern" and "vibrate on the spot" — to the state where particles cannot move past each other.

💡 Hint 3 — set up the first step

Gas: far apart, fast, random.
Liquid: close but able to slide past each other.
Fixed pattern + vibrate only = the most ordered state.

Use the particle model.

Only a solid holds particles in a fixed lattice where they vibrate without moving past each other.
Liquids let particles slide; gases spread to fill the container.

✅ Answer: C — Solid

Why this is the answer: a regular fixed arrangement with vibration-only motion is the defining picture of a solid. Revise: Lesson 1.

⭐ Q2Y7-8 Stage 4Difficulty ★★Particle model › density

The Problem

A block of aluminium has a mass of 54 g and a volume of 20 cm³. What is its density? (density = mass ÷ volume)

Your answer

❓ What is the density?

A 0.37 g/cm³
B 2.7 g/cm³
C 27 g/cm³
D 74 g/cm³
E 1080 g/cm³

🎯 Knowledge Point — what this tests

Density links mass and volume: density = mass ÷ volume. Watch the order — mass on top.

Divide mass by volume; check the size of the answer is sensible (metals are a few g/cm³, not hundreds).

💡 Hint 3 — set up the first step

density = 54 ÷ 20.
54 ÷ 20 = 2.7.
Units: g ÷ cm³ = g/cm³.

Apply the formula.

density = mass ÷ volume = 54 g ÷ 20 cm³ = 2.7 g/cm³.
A inverts the formula; C/D/E mis-place the decimal or multiply.

✅ Answer: B — 2.7 g/cm³

Why this is the answer: 54 divided by 20 is 2.7, and the units come out as g/cm³ — the real density of aluminium. Revise: Lesson 2.

⭐ Q3Y7-8 Stage 4Difficulty ★Classifying matter › compound

The Problem

Which of the following substances is a compound?

Your answer

❓ Which one is a compound?

A Oxygen gas (O₂)
B Iron filings (Fe)
C Carbon dioxide (CO₂)
D Air
E Brass

🎯 Knowledge Point — what this tests

A compound is two or more different elements chemically bonded in a fixed ratio. An element has one kind of atom; a mixture is not chemically bonded.

Sort each option into element, compound or mixture, then pick the chemically-bonded one.

💡 Hint 3 — set up the first step

O₂ and Fe = elements (one kind of atom).
Air and brass = mixtures (not chemically bonded).
CO₂ = carbon + oxygen bonded together.

Classify each.

CO₂ is carbon and oxygen chemically bonded → a compound.
O₂, Fe are elements; air is a gas mixture; brass is a copper–zinc alloy (mixture).

✅ Answer: C — Carbon dioxide (CO₂)

Why this is the answer: only CO₂ contains two different elements chemically joined in a fixed ratio. Revise: Lesson 3.

⭐ Q4Y7-8 Stage 4Difficulty ★★Classifying matter › pure vs impure

The Problem

A pure substance, unlike a mixture, will:

Your answer

❓ Which statement is true of a pure substance?

A always be a metal
B melt over a wide range of temperatures
C melt at one sharp, fixed temperature
D always dissolve in water
E always contain two or more elements

🎯 Knowledge Point — what this tests

Purity is tested by melting/boiling point: a pure substance has a single sharp value; a mixture melts/boils over a range.

Eliminate "always" statements that aren't true of every pure substance, then use the melting-point test.

💡 Hint 3 — set up the first step

Pure substances can be metals or non-metals (A wrong).
A range of melting temperatures signals impurity (B describes a mixture).
A pure substance can be an element or a compound (E wrong).

Use the melting-point test.

A pure substance melts at one sharp, fixed temperature; impurities spread the melting over a range.
The other options are not true of every pure substance.

✅ Answer: C — melt at one sharp, fixed temperature

Why this is the answer: a single sharp melting point is the standard lab test for purity. Revise: Lesson 4.

⭐ Q5Y7-8 Stage 4Difficulty ★Solutions › solute & solvent

The Problem

In a cup of salt water, the salt is the ______ and the water is the ______.

Your answer

❓ Which pair fills the blanks?

A solvent; solute
B solute; solvent
C solution; solute
D mixture; compound
E solvent; solution

🎯 Knowledge Point — what this tests

The solute dissolves; the solvent does the dissolving; together they make a solution.

Decide which substance disappears (dissolves) and which one it dissolves into.

💡 Hint 3 — set up the first step

The salt disappears into the water → salt is the solute.
The water does the dissolving → water is the solvent.

Name the parts.

Salt dissolves → solute. Water dissolves it → solvent. The salt water is the solution.

✅ Answer: B — solute; solvent

Why this is the answer: the dissolved substance is the solute and the dissolving liquid is the solvent. Revise: Lesson 5.

⭐ Q6Y7-8 Stage 4Difficulty ★Solutions › saturation

The Problem

A solution in which no more solute can dissolve at a given temperature is described as:

Your answer

❓ What is this solution called?

A dilute
B unsaturated
C saturated
D insoluble
E concentrated but unsaturated

🎯 Knowledge Point — what this tests

"Saturated" means the solvent has dissolved all the solute it can hold at that temperature; extra solute just sits at the bottom.

"Dilute" and "concentrated" describe how much is dissolved, not whether the limit is reached. Look for the word that means "full".

💡 Hint 3 — set up the first step

Can still dissolve more → unsaturated.
Cannot dissolve any more → saturated.

Use the definition.

No more solute dissolves at that temperature → the solution is saturated.
Dilute/concentrated only describe amount; insoluble means it won't dissolve at all.

✅ Answer: C — saturated

Why this is the answer: a saturated solution holds the maximum solute possible at that temperature. Revise: Lesson 6.

⭐ Q7Y7-8 Stage 4Difficulty ★Separating › filtration

The Problem

Which method best separates a mixture of sand and water?

Your answer

❓ Which separation method?

A Evaporation
B Filtration
C Distillation
D Chromatography
E Using a magnet

🎯 Knowledge Point — what this tests

Choose the method by the property that differs. Sand is insoluble and bigger than the filter holes; water passes through.

Ask: is the solid dissolved? Sand does not dissolve, so a simple physical filter works.

💡 Hint 3 — set up the first step

Sand is insoluble → it stays as a solid.
Filter paper lets water through and traps the sand.

Match property to method.

Sand is an insoluble solid → filtration traps it while water passes through.
Evaporation/distillation are for dissolved substances; a magnet only works on magnetic solids.

✅ Answer: B — Filtration

Why this is the answer: an insoluble solid in a liquid is separated by filtration. Revise: Lesson 7.

⭐ Q8Y7-8 Stage 4Difficulty ★★Separating › distillation

The Problem

Which method would you use to obtain pure water from salt water, keeping the water?

Your answer

❓ Which method keeps the water?

A Filtration
B Simple distillation
C Evaporation to dryness
D Decanting
E Chromatography

🎯 Knowledge Point — what this tests

Salt is dissolved, so filtration can't remove it. To keep the water you must evaporate it and then catch the vapour by cooling it back to liquid.

The key words are "keeping the water". Evaporation to dryness throws the water away; you need a method that collects it.

💡 Hint 3 — set up the first step

Filtration fails — salt is dissolved, not a solid lump.
Evaporation to dryness leaves the salt but loses the water.
Distillation boils off the water and condenses it back — pure water collected.

Keep the liquid by condensing it.

Simple distillation boils the water away from the salt, then cools the vapour back to pure liquid water.
Evaporation keeps the salt but loses the water; filtration/decanting can't separate dissolved salt.

✅ Answer: B — Simple distillation

Why this is the answer: distillation is the only listed method that recovers the water itself from a solution. Revise: Lesson 8.

⭐ Q9Y7-8 Stage 4Difficulty ★Atomic structure › subatomic particles

The Problem

Which subatomic particle has a negative charge and almost no mass?

Your answer

❓ Which particle?

A Proton
B Neutron
C Electron
D Nucleus
E Ion

🎯 Knowledge Point — what this tests

Protons are positive, neutrons are neutral — both sit in the nucleus and have mass ≈ 1. Electrons are negative and almost massless.

Match both clues: negative charge AND negligible mass.

💡 Hint 3 — set up the first step

Proton = +1, mass 1. Neutron = 0, mass 1.
The light, negative one is the electron.

Recall the three particles.

The electron carries a −1 charge and has a mass about 1/1836 of a proton — effectively zero.
"Nucleus" is the centre (protons + neutrons); an ion is a charged atom, not a subatomic particle.

✅ Answer: C — Electron

Why this is the answer: only the electron is both negative and near-massless. Revise: Lesson 11.

⭐ Q10Y7-8 Stage 4Difficulty ★★Atomic structure › mass number

The Problem

An atom has 11 protons, 12 neutrons and 11 electrons. What is its mass number?

Your answer

❓ What is the mass number?

A 11
B 12
C 22
D 23
E 34

🎯 Knowledge Point — what this tests

Mass number = number of protons + number of neutrons. Electrons are too light to count.

Add protons and neutrons only; ignore the electrons.

💡 Hint 3 — set up the first step

Mass number = protons + neutrons.
= 11 + 12.

Add the heavy particles.

Mass number = protons + neutrons = 11 + 12 = 23.
11 is the atomic number (protons only); 34 wrongly adds the electrons too.

✅ Answer: D — 23

Why this is the answer: mass number counts protons plus neutrons (11 + 12 = 23) — this atom is sodium. Revise: Lesson 11.

⭐ Q11Y7-8 Stage 4Difficulty ★Periodic table › metals vs non-metals

The Problem

Which is a typical property of most non-metals (as solids)?

Your answer

❓ Which property fits non-metals?

A Good conductor of electricity
B Shiny and malleable
C Dull and brittle
D Always magnetic
E Sonorous (rings when hit)

🎯 Knowledge Point — what this tests

Metals are shiny, malleable, conductive and sonorous. Non-metals are usually the opposite: dull, brittle and poor conductors.

Options A, B and E are all classic metal properties — eliminate them.

💡 Hint 3 — set up the first step

Conductor / shiny / sonorous → metals.
Dull and brittle → non-metals.

Contrast metals and non-metals.

Most solid non-metals are dull and brittle and do not conduct electricity (graphite is the famous exception).
A, B, E describe metals; magnetism is rare, not typical.

✅ Answer: C — Dull and brittle

Why this is the answer: dull, brittle, non-conducting solids are typical non-metals. Revise: Lesson 13.

⭐ Q12Y7-8 Stage 4Difficulty ★★Periodic table › groups & electrons

The Problem

Elements in the same group (vertical column) of the periodic table have the same:

Your answer

❓ What do elements in a group share?

A number of neutrons
B mass number
C number of electrons in their outer shell
D number of protons
E density

🎯 Knowledge Point — what this tests

Group number tells you the number of outer-shell (valence) electrons, which is why a group reacts in similar ways.

Proton number changes down a group (D wrong). What stays the same is the outer-shell electron count.

💡 Hint 3 — set up the first step

Across a period, properties change; down a group, they're similar.
Similar reactions come from the same number of outer electrons.

Link group to electrons.

Elements in a group share the same number of outer-shell electrons, so they react similarly (e.g. Group 1 all very reactive metals).
Proton and neutron counts differ down a group.

✅ Answer: C — number of electrons in their outer shell

Why this is the answer: shared valence-electron count is what gives a group its similar chemistry. Revise: Lesson 14.

⭐ Q13Y7-8 Stage 4Difficulty ★Reactions › physical vs chemical

The Problem

Which of the following is a chemical change?

Your answer

❓ Which one is a chemical change?

A Ice melting
B Sugar dissolving in water
C Iron rusting
D Water boiling
E Crushing a can

🎯 Knowledge Point — what this tests

A chemical change makes a new substance and is hard to reverse. A physical change (melting, dissolving, boiling, crushing) makes no new substance.

Ask for each: is a new substance formed? Only one option does.

💡 Hint 3 — set up the first step

Melting, dissolving, boiling, crushing → physical, no new substance.
Rusting forms iron oxide → a new substance.

Test for a new substance.

Iron rusting forms iron oxide — a new substance — so it is a chemical change.
The others are physical changes that can be reversed and make nothing new.

✅ Answer: C — Iron rusting

Why this is the answer: only rusting produces a new substance (iron oxide). Revise: Lesson 15.

⭐ Q14Y7-8 Stage 4Difficulty ★Reactions › word equations

The Problem

In the reaction magnesium + oxygen → magnesium oxide, the magnesium and oxygen are the:

Your answer

❓ What are magnesium and oxygen here?

A products
B reactants
C catalysts
D solvents
E mixtures

🎯 Knowledge Point — what this tests

In a word equation, the substances before the arrow are reactants; the substance after the arrow is the product.

Find the arrow. Everything on the left is what you start with.

💡 Hint 3 — set up the first step

Left of arrow = starting materials = reactants.
Right of arrow = what is made = product.

Read the arrow.

Magnesium and oxygen are on the left, so they are the reactants; magnesium oxide is the product.
A catalyst speeds a reaction without being used up — not the case here.

✅ Answer: B — reactants

Why this is the answer: substances before the arrow are the reactants. Revise: Lesson 16.

⭐ Q15Y7-8 Stage 4Difficulty ★Energy › exo vs endothermic

The Problem

When a reaction releases heat to the surroundings and the temperature rises, the reaction is:

Your answer

❓ What type of reaction is it?

A endothermic
B exothermic
C a physical change only
D always reversible
E neutralisation

🎯 Knowledge Point — what this tests

Exo = out: heat goes out, surroundings warm up. Endo = in: heat is taken in, surroundings cool down.

Temperature rises → heat was released → the prefix is "exo".

💡 Hint 3 — set up the first step

Heat released, surroundings get hotter → exothermic.
Heat absorbed, surroundings get colder → endothermic.

Use exo = out.

Releasing heat so the temperature rises is the definition of an exothermic reaction (e.g. combustion).
Endothermic absorbs heat and feels cold.

✅ Answer: B — exothermic

Why this is the answer: releasing heat to warm the surroundings is exothermic. Revise: Lessons 17–18.

🏁 Finish

That's the end of the exam

Go back and change any answers you like. When you're ready, submit the whole exam to lock it in and see your knowledge report — then you can revisit every question to read the full worked solution.

The report stays locked until you submit — you can't open it early.

📊 Diagnostic Report

Your knowledge-point report

Here is how you performed on every knowledge area you attempted. Bars show your accuracy per topic — green is strong, amber is shaky, red needs work. Only questions you answered are scored.

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