rate of reaction test

Question 1

2 pieces of measuring apparatus to find the rate of production of gas

Answer 1

gas syringe

stopwatch

Question 2

3 conclusions about the rate of reaction between magnesium and dilute hydrochloric acid

Answer 2

• rate of reaction is fastest between 0 and 10 secs
• rate of reaction decreases between 0 and 60 secs
• all of the acid has reacted by 60 secs

Question 3

correct statements

Answer 3

more bubbles were produced in the first 10 secs

magnesium was used up more quickly

Question 4

change to apparatus to improve accuracy

Answer 4

using a polystyrene cup instead of a glass beaker to minimise energy transfer to the surroundings

Question 5

control variable to use

Answer 5

concentration of hydrochloric acid

Question 6

uncertainty

Answer 6

+- 0.2

Question 7

possible error other than anomalous point

Answer 7

poor stirring so not all element had dissolved

Question 8

yield if temperature is higher than 250C

Answer 8

decreases because the backwards reaction is endothermic so the equilibrium would move to the left in order to oppose the increase in temp

Question 9

how does a catalyst increase the rate of reaction

Answer 9

provides alternate route which has a lower activation energy so, less energy is needed for the reaction to take place.

Question 10

why does a higher pressure give a greater yield of methanol and increased rate of reaction

Answer 10

less moles on right side of the equation so, increasing the pressure moves the equilibrium to the right in order to decrease the pressure

increased pressure means there are more molecules in a given volume so more frequent successful collisions.