Chemical World Investigating how concentration affects the rate of a reaction
Using a plastic canister or a bottle with a lid that pops off, vinegar and baking powder, make a rocket that launches after 60 seconds.
While designing this investigation, consider the following:
1. What variables will you keep the same?
2. What variables will you change? 3. What safety precautions do you need to take? 4. What energy transfers are happening in this investigation? 5. What changes would you make to get the rocket to launch after 30 seconds?
z Fig. 12.4.4
Experiment materials for making a bottle-top rocket: A plastic bottle with a lid that pops off, vinegar and baking powder
The materials needed to make a bottle rocket
Surface Area and Rate of Reaction
Particle size is used to compare the dimensions of the particles in solids. As a particle size gets smaller, the surface area increases. Surface area is a measure of how much of a substance is exposed.
Predict which of the pots of potatoes in Fig 12.4.5 will cook first. Explain your prediction.
z
Fig. 12.4.5
Cutting the potato into smaller parts increases its surface area. The larger the surface area, the greater the area available for collisions to take place. Increasing the surface area increases the rate of a reaction.
Learn more about measuring in Physical World 15.2
Very finely divided particles may cause a ‘dust explosion’. This is a danger in flour mills, grain storage and coalmines, where a build-up of dust in the air can lead to an explosion.
