AQA GCSE Chemistry Chemistry Paper 1 (Foundation), June 2024: Question 4
10 marks · Low Demand difficulty · Short Answer
Identify properties and uses of nanoparticles, select a transition metal catalyst, and calculate the surface area to volume ratio of a cubic nanoparticle.
Practise this questionQuestion
Question text
04 This question is about small particles.
04.1 What is the approximate number of atoms in a nanoparticle?
[1 mark]
Tick ( ) one box.
A few hundred atoms
A few thousand atoms
A few million atoms
A few billion atoms
04.2 Nanoparticles of some elements can be used as catalysts.
Which element is most likely to be used as a catalyst?
Use the periodic table.
[1 mark]
Tick ( ) one box.
Aluminium
Iron
Magnesium 20
04.3 Nanoparticles are used in sun creams and in wound dressings.
A wound dressing is placed next to the skin to prevent infection.
Figure 8 shows a wound dressing.
Figure 8
Table 2 shows some information about substances used in the form of nanoparticles.
Table 2
Substance Property
Carbon Strong
Silicon dioxide Hard
Silver Kills bacteria
Titanium dioxide21 Blocks light
Draw one line from each use to the best substance for that use.
[2 marks]
Use Substance
Carbon
Sun creams Silicon dioxide
Silver
Wound dressings
22 Titanium dioxide
04.4 Figure 9 shows a cubic nanoparticle.
Figure 9
Calculate:
• the surface area of the cubic nanoparticle
• the volume of the cubic nanoparticle
• the simplest whole number ratio of surface area : volume for the cubic nanoparticle.
Use the equation:
surface area of cubic nanoparticle = 6 × surface area of one face
[6 marks]
Surface area of cubic nanoparticle = nm2
Volume of cubic nanoparticle = nm3
Simplest whole number ratio of surface area: volume = :
Mark scheme
Show the mark scheme
Question 4
AO /
Question Answers Extra information Mark
Spec. Ref.
04.1 a few hundred atoms 1 AO1
4.2.4.1
AO /
Spec. Ref.
04.2 iron 1 AO3
4.1.3.2
AO /
Question Answers Mark
Spec. Ref.
04.3 AO3
4.2.4.2
– – –
do not accept more than one line from a box on the left
AO /
Spec. Ref.
04.4 (surface area =) 6 × 42 1 AO2
4.2.4.1
= 96 (nm2) 1
(volume =) 43 1
= 64 (nm3) 1
(ratio =) 96 : 64 allow correct use of incorrectly 1
determined area and/or volume
= 3 : 2 allow correct use of an 1
incorrectly determined ratio
Total Question 4 10
How to answer it
Nanoparticles: Properties, Uses & Calculations
What this question tests:
- Recall of the scale and atomic composition of nanoparticles.
- Linking elements to their chemical functions (catalysis and transition elements).
- Applying given properties of nanomaterials to real-world uses (silver and titanium dioxide).
- Step-by-step mathematical calculations: surface area of a 3D cube, volume, and reducing a surface area-to-volume ratio to its simplest whole numbers.
Question 04.1: Particle Scale
Number of atoms in a nanoparticle (1 mark)
✅ Correct Answer
A few hundred atoms
💡 Key Knowledge
Nanoparticles range in size from 1 to 100 nm across. A typical nanoparticle contains only a few hundred atoms, making them larger than individual atoms/small molecules, but vastly smaller than fine particles or macroscopic matter.
❌ Common Errors
Students often tick "a few million" or "a few billion". While a macroscopic grain of sand has trillions of atoms, nanoparticles are unimaginably small and contain only hundreds of atoms.
Question 04.2: Catalysts & Periodic Table
Choosing the catalyst element (1 mark)
✅ Correct Answer
Iron
🧠 Exam Technique
The prompt says "Use the periodic table". This is your clue to check where these metals sit:
- Iron is a transition metal (found in the central block). Transition metals and their compounds are classic catalysts (e.g. Haber process).
- Aluminium (Group 3) and Magnesium (Group 2) are main-group metals and rarely used as elemental catalysts.
Question 04.3: Applications of Nanoparticles
Matching use to substance (2 marks)
✅ Correct Answers
- Sun creams ➔ Titanium dioxide [1 mark]
- Wound dressings ➔ Silver [1 mark]
💡 Property-to-Use Matching
Use the data given in Table 2 directly:
- Sun creams: Need to block UV rays ➔ Property: Blocks light ➔ Titanium dioxide.
- Wound dressings: Need to prevent infection ➔ Property: Kills bacteria (antimicrobial) ➔ Silver.
❌ Common Errors & Examiner Warning
Rule check: The mark scheme specifically states: "do not accept more than one line from a box on the left". If you draw two lines emerging from "Sun creams", that mark is automatically lost—even if one of your lines points to titanium dioxide!
Question 04.4: Surface Area, Volume & Ratio Calculations
Cube dimensions: 4 nm × 4 nm × 4 nm (6 marks)
📐 Step-by-Step Calculation
Step 1: Calculate Total Surface Area
- Area of one face = 4 nm × 4 nm = 16 nm²
- Formula provided: surface area = 6 × surface area of one face
- Total Surface Area = 6 × 16 = 96 nm²
- ➔ 2 marks: [1 mark for formula/working 6 × 4², 1 mark for 96]
Step 2: Calculate Volume
- Volume of a cube = length × width × height = 4³
- Volume = 4 × 4 × 4 = 64 nm³
- ➔ 2 marks: [1 mark for working 4³, 1 mark for 64]
Step 3: Determine Simplest Whole Number Ratio (Surface Area : Volume)
- Initial ratio = 96 : 64 [1 mark]
- Divide both sides by the greatest common divisor (32):
96 ÷ 32 = 3
64 ÷ 32 = 2 - Simplest whole number ratio = 3 : 2 [1 mark]
🧠 Exam Technique: Error Carried Forward (ECF)
Notice the mark scheme allows "correct use of incorrectly determined area and/or volume". Even if you made an arithmetic slip in Step 1 or Step 2, you can still gain the final 2 marks by correctly stating and simplifying the ratio of your calculated numbers!
❌ Common Errors
- Reversing the ratio: Writing 2 : 3 instead of 3 : 2 . The question asks for surface area : volume.
- Forgetting all 6 faces: Calculating only one face ( 16 nm² ) and failing to multiply by 6.
- Not simplifying: Leaving the answer as 96 : 64 or 48 : 32 . Always divide down until no common factors remain!
Topics
Chemistry · C1: Atomic Structure and the Periodic Table · C2: Bonding, Structure and the Properties of Matter
Question and mark scheme from the AQA GCSE Chemistry examination, Chemistry Paper 1 (Foundation), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.