Boardworks Diffusion Worksheet | PDF - Free Printable

Let's solve the Diffusion Worksheet step by step, analyzing each pair of diagrams and explaining which one will have a faster diffusion rate based on the principles of diffusion.

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🔬 What is Diffusion?

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration until equilibrium is reached. The rate of diffusion depends on:

1. Concentration gradient – the greater the difference in concentration, the faster the diffusion.
2. Temperature – higher temperature increases particle kinetic energy, increasing diffusion rate.
3. Surface area and membrane permeability – but these are constant here.

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Now let’s go through each part:

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✔ Question 1a)

#### i) vs ii)

- Both show glucose molecules (diamonds) on either side of a membrane.
- In i): There are fewer glucose molecules above the membrane and one below → small concentration gradient.
- In ii): There are many glucose molecules above and only one below → large concentration gradient.

✔ Answer:
ii) will have a faster diffusion rate because there is a greater concentration gradient (more glucose on one side), so particles move more rapidly across the membrane.

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✔ Question 1b)

#### i) vs ii)

- In i): Glucose molecules are spread out, with a few on both sides.
- In ii): Glucose molecules are more concentrated on the top side and fewer on the bottom.

Compare:
- i): Concentration on top = ~6, bottom = ~2 → gradient = 4
- ii): Concentration on top = ~8, bottom = ~2 → gradient = 6

✔ Answer:
ii) has a larger concentration gradient, so diffusion will be faster in ii).

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✔ Question 1c)

#### i) vs ii)

- Both have the same number of glucose molecules (same concentration gradient).
- But i) is at 0°C (cold), and ii) is at 80°C (hot).

💡 Higher temperature means:
- Molecules have more kinetic energy
- Move faster
- Collide more frequently
→ So, diffusion rate increases

✔ Answer:
ii) will have a faster diffusion rate because temperature is higher, increasing molecular movement.

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📝 Final Answers:

#### a)
- i): Small gradient → slower diffusion
- ii): Large gradient → faster diffusion
➡️ Faster in ii) due to greater concentration gradient

#### b)
- i): Moderate gradient
- ii): Larger gradient
➡️ Faster in ii) due to greater concentration gradient

#### c)
- i): 0°C → slow molecular motion
- ii): 80°C → fast molecular motion
➡️ Faster in ii) due to higher temperature

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✔ Summary Table:

| Pair | Faster Diffusion | Reason |
|------|------------------|--------|
| a) | ii) | Greater concentration gradient |
| b) | ii) | Greater concentration gradient |
| c) | ii) | Higher temperature increases particle movement |

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This worksheet helps reinforce how concentration gradients and temperature affect the rate of diffusion — key concepts in IGCSE Biology!