Rates of Reaction

Question 1

Measuring rate of reaction using mass of gas

Answer 1

• Use a measuring cylinder to measure 25cm3 of dilute acid
• Add reactant to a conical flask and place cotton wool on the opening
• Place everything on a balance and set it to 0
• Add the acid to the conical flask and measure the mass every 30s
• Plot mass against time taken
• Change independent variable and repeat with new equipment

Question 2

Measuring rate of reaction using volume of gas

Answer 2

• Measure 25cm3 of dilute acid to a conical flask
• Add excess reactant and place a bung over the flask
• Measure the volume of gas in gas syringe/measuring cylinder every 30s
• Plot volume against time taken
• Change independent variable and repeat with new equipment

Question 3

Catalyst

Answer 3

A substance that increases rate of reaction but is chemically unchanged at the end of reaction

Question 4

How do catalysts work?

Answer 4

By providing an alternative pathway with lower activation energy

Question 5

The greater the surface area of a solid…

Answer 5

The more particles are available for collisions, therefore the frequency of collisions and rate of reaction increases

Question 6

The greater the concentration of a fluid…

Answer 6

The greater number of particles within a fixed volume, therefore a greater frequency of successful collisions and rate of reaction

Question 7

The greater the temperature…

Answer 7

The more kinetic energy the particles have an therefore the faster they travel, increasing the frequency of collisions. Furthermore the increase in energy results in more particles with greater energy than the activation energy and therefore a greater frequency of successful collisions and rate of reaction