Measuring Rates Of Reactions

Question 1

What is the formula for calculating the rate of reaction?

Answer 1

Question 2

What unit of measure do we measure a gas reactant or product in a chemical reaction ?

Answer 2

cm^3

Question 3

What unit of measure do we measure a solid reactant or product in a chemical reaction ?

Answer 3

grams (g)

Question 4

What is time measured when calculating a rate of reaction?

Answer 4

seconds

Question 5

What units are used for the rate of reaction?

Answer 5

•cm^3/s or g/s
•sometimes the volume of reactant or product can be measured in moles so it could also be mol/s

Question 6

How could u measure the rate of a reaction using precipitation or colour change?

Answer 6

1) For reactions with transparent initial solutions forming a precipitate product (opaque) , observe how long it takes for a mark to disappear through the solution
2) If reactants and products have different colors, time how long it takes for the solution to change color.
3) the results for this are very subjective as different people may not agree over the exact point when the mark disappears or the solution changes colour. You can also not plot a rate of reaction graph from the result

Question 7

How could u measure the rate of a reaction by measuring the change in mass (usually given off)?

Answer 7

1)as the gas is released the mass disappearing is measured on the balance
2)the quicker the reading on the balance drops the faster the reaction
3) This is very accurate because the mass balance is very accurate however has the disadvantage of releasing gas straight into the room

Question 8

How could u measure the rate of a reaction by measuring the volume of gas given off?

Answer 8

1)this involves using a gas syringe to measure the volume of gas given off
2)the more gas given off during a given time interval the faster the reaction
3)this is quite accurate as the volumes are given to the nearest cm^3 and you can plot a rate of reaction graph using this method
4)a disadvantage to this is if the reaction is too vigorous you can easily blow the plunger out of the end of the syringe

Question 9

How do you find the mean rate of reaction from a rate of reaction graph?

Answer 9

Calculate the gradient (change in y/change in x)

Question 10

How do you find the reaction rate at a particular point on a rate of reaction graph?

Answer 10

1) draw a tangent to the point
2)calculate the gradient of the tangent