Combined Science: units and calculations practice sheet
This sheet covers Physics/Chemistry foundations. Choose questions that belong to your science combination. For every calculation, underline the quantity requested, write the equation, convert the units and finish with a reasonableness check. It is original practice, not a past paper or an official marking scheme.
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Question 1
A 3.0 kg object rises 2.0 m. Take g = 10 N/kg. Find the gravitational potential energy gained.
My method: ____________________
My working: ____________________
My check: ____________________
Question 2
A 12 V ideal supply connects 4 Ω and 8 Ω resistors in series. Find the current and the voltage across the 8 Ω resistor.
My method: ____________________
My working: ____________________
My check: ____________________
Question 3
Find the amount in 40.0 cm³ of 0.150 mol/dm³ solution.
My method: ____________________
My working: ____________________
My check: ____________________
Question 4
2Mg + O₂ → 2MgO. Find the mass of MgO from 3.60 g Mg in excess oxygen. Use Mg = 24 and O = 16.
My method: ____________________
My working: ____________________
My check: ____________________
Worked answers
Answer 1
- Energy = mgh = 3.0 × 10 × 2.0.
- The gain is 60 J.
Answer 2
- Total resistance = 12 Ω, so current = 12/12 = 1 A.
- Voltage across 8 Ω = 1 × 8 = 8 V. The remaining 4 V is across the other resistor.
Answer 3
- Volume = 0.0400 dm³.
- n = cV = 0.150 × 0.0400 = 0.00600 mol.
Answer 4
- n(Mg) = 3.60/24 = 0.150 mol. The mole ratio to MgO is 1:1.
- Mass of MgO = 0.150 × 40 = 6.00 g.
My next revision step
| Question | First mistake | What I will check next time |
|---|---|---|
| 1 | ____________ | ____________ |
| 2 | ____________ | ____________ |
| 3 | ____________ | ____________ |
| 4 | ____________ | ____________ |
Read the complete revision lessons
Scope and review
Official 2026 syllabus. Original AI-assisted practice; selected numerical results and their displayed working are automatically checked. This does not verify every explanation. No teacher review or exam-board endorsement is claimed.