Measuring Rates

Question 1

Method for measuring rage by continuous monitoring for Mg and HCl

Answer 1

Measure volume of HCl into conical flask and add Mg
Connect gas syringe
Measure volume of H2 gas produced regularly

Question 2

How to calculate rate from time v volume graph from continuous monitoring method

Answer 2

Tangent at t=0

Calculate gradient

Question 3

Method to find rate by measuring change in mass

CaCO3 and HCl

Answer 3

Known volume of HCl added to conical flask
Place flask on balance and record initial mass
add solid
Mass of flask will decrease
Measure mass regularly
Deduce rate from gradient of graph

Question 4

Method to measure rate using initial rates

Answer 4

Prepare 2 separate beakers, one contains reagent A and indicator, and the other containing B and any catalysts
Mix beakers and start timer immediately
Stop the clock when indication is given that reaction is complete
Repeat with varied concentrations of A

Question 5

Data analysis for initial rates method

Answer 5

Use 1/t

Plot graph of 1/t against concentration

Question 6

Why is 1/t proportional to rate for initial rates method

Answer 6

Concentration of product at end point is fixed

Therefore it is taken as constant

Question 7

What does zero order graph look like for 1/t vs concentration graph

Answer 7

Straight line

Question 8

What does first order graph look like for 1/t vs concentration graph

Answer 8

Straight line through origin (constant gradient)

Question 9

What does second order graph look like for 1/t vs concentration graph

Answer 9

Exponential

Question 10

How to improve measuring rates when using a measuring cylinder in a water trough

Answer 10

Quickly but bung in

Start time at first bubble to eliminate initial delay

Question 11

How to calculate order from a time/ volume graph

Answer 11

Gradient at different times