Mini practice paper: 8 questions
Mixed-difficulty questions from across the Sciences syllabus. Tap "Show answer" after each to check yourself.
Q1 · Difficulty 1/3
A student adds dilute hydrochloric acid to a white powder. A colourless gas is produced that turns limewater milky. Which anion is present in the powder?
- B: Carbonate ion (CO₃²⁻)
- C: Chloride ion (Cl⁻)
- D: Nitrate ion (NO₃⁻)
- A: Sulfate ion (SO₄²⁻)
Show answer & explanation
✓ Answer: A — B: Carbonate ion (CO₃²⁻)
Carbonate ions react with dilute hydrochloric acid to produce carbon dioxide gas, which turns limewater milky (forms a white precipitate of calcium carbonate). Sulfate ions produce a white precipitate with barium chloride, not a gas with HCl. Chloride ions are detected using silver nitrate solution. Nitrate ions do not produce a gas with dilute HCl.
Q2 · Difficulty 1/3
How does increasing concentration affect rate?
- It slows the reaction
- More particles in the same volume means more frequent collisions, increasing rate
- No effect
- It only affects temperature
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✓ Answer: B — More particles in the same volume means more frequent collisions, increasing rate
Higher concentration = more particles per unit volume = more frequent successful collisions = faster rate.
Q3 · Difficulty 1/3
Which organelle is the main site of photosynthesis in plant cells?
- Vacuole
- Chloroplast
- Mitochondrion
- Ribosome
Show answer & explanation
✓ Answer: B — Chloroplast
Chloroplasts contain chlorophyll, which absorbs light energy to drive photosynthesis. Mitochondria are the site of aerobic respiration, not photosynthesis. Ribosomes are involved in protein synthesis. Vacuoles store cell sap and help maintain turgor pressure.
Q4 · Difficulty 1/3
What is selective breeding?
- Natural selection
- Humans choosing organisms with desired characteristics to breed over generations
- Genetic engineering
- Cloning
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✓ Answer: B — Humans choosing organisms with desired characteristics to breed over generations
Also called artificial selection. Farmers/breeders choose parents with desired traits → breed → select best offspring → repeat for many generations. Used for crops, livestock, dogs.
Q5 · Difficulty 1/3
What is radioactive decay?
- The spontaneous and random emission of radiation from unstable nuclei
- Nuclear fusion
- Combustion
- A chemical reaction
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✓ Answer: A — The spontaneous and random emission of radiation from unstable nuclei
Radioactive decay is random (cannot predict which nucleus decays next) and spontaneous (happens without external input). The nucleus emits alpha, beta, or gamma radiation to become more stable.
Q6 · Difficulty 1/3
What is a pure substance in chemistry?
- Any liquid
- Any clean substance
- A substance made of only one type of element or compound with a fixed melting/boiling point
- Filtered water
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✓ Answer: C — A substance made of only one type of element or compound with a fixed melting/boiling point
A pure substance has a sharp, fixed melting point. Impurities lower the melting point and broaden the range. Pure water boils at exactly 100°C.
Q7 · Difficulty 1/3
Which of the following is the correct equation linking pressure, volume, and temperature for a fixed mass of gas?
- P₁V₁/T₂ = P₂V₂/T₁
- P₁/T₁ = P₂V₂/T₂
- P₁V₁T₁ = P₂V₂T₂
- P₁V₁/T₁ = P₂V₂/T₂
Show answer & explanation
✓ Answer: D — P₁V₁/T₁ = P₂V₂/T₂
The combined gas law for a fixed mass of gas is P₁V₁/T₁ = P₂V₂/T₂, where temperature must be in Kelvin. Option A is incorrect because the temperatures are multiplied rather than dividing PV. Options B and D rearrange the terms incorrectly, placing variables in the wrong positions.
Q8 · Difficulty 1/3
What is the test for hydrogen gas?
- Turns damp litmus paper white
- Turns limewater milky
- A lit splint produces a squeaky pop
- Relights a glowing splint
Show answer & explanation
✓ Answer: C — A lit splint produces a squeaky pop
Hold a lit splint at the mouth of the test tube. If hydrogen is present, it burns with a squeaky pop sound.
Edexcel GCSE Sciences FAQ
What does the Edexcel GCSE Sciences exam look like?
The Edexcel GCSE Sciences exam is structured across 3 components. Paper 1: Approximately 1 hour 30 minutes, ~70-100 marks. Covers Topics 1-4 of the specification. Paper 2: Approximately 1 hour 30 minutes, ~70-100 marks. Covers Topics 5-8 of the specification. Paper 3: Where applicable — e.g. Combined Science, Languages. Includes synoptic and applied questions. Total exam time: ~3 hours across two or three papers.
Can I download a free Edexcel GCSE Sciences past paper?
Real Edexcel past papers are published directly by Edexcel on their official website. Kramizo doesn't redistribute copyrighted past papers, but we do generate free AI-written practice papers in the exact same style — same command words, same difficulty tier, same mark conventions. Use this practice paper as warm-up, then time yourself on official past papers before exam day.
How is Edexcel GCSE Sciences graded?
Grades: 9 (highest) to 1 (lowest), with U (ungraded). A grade of 4 is a standard pass; 5 is a strong pass. Kramizo's practice questions are tagged with difficulty 1-3 mapping roughly to the lower, middle, and top grade boundaries you'll encounter in the real exam.