C4 Quantitive Chemistry

Question 1

Atom economy

Answer 1

Measure of efficiency of a chemical reaction

Question 2

How to calculate a titre

Answer 2

The values are added together and divided by the readings

Question 3

How concentration of a solution can be changed

Answer 3

Can be increased by dissolving more solute in a given volume of solution

Question 4

Why using reactions with high atom economy is important

Answer 4

Uses fewer natural resources and less waste

Question 5

Theoretical yield

Answer 5

Amounts of products calculated from the complete reaction of the limiting reagent

Question 6

Actual yield

Answer 6

The quantity of a product found to be formed in a chemical reaction

Question 7

Why chemical equations must be balanced

Answer 7

To abide by the law of conservation of mass

Question 8

Effect of a limiting reactant on the amount of product made

Answer 8

No more product can form when the limiting reactant is all used up

Question 9

How the volume of gas would change when temperature or pressure was changed

Answer 9

If the container holding a gas is flexible the volume will increase

Question 10

How to caclulate atom economy

Answer 10

Mass of desired products
____________________________ x 100

  mass of products

Question 11

How accuracy can be improved in a titration

Answer 11

Titrate less sample

Question 12

How an indicator can be used to determine the end point

Answer 12

Helps us to visually spot the equivalence point in an acid-base titration

Question 13

Why is actual yield is often lower than theoretical yield

Answer 13

Due to loss in the process or inefficiency of the chemical reaction

Question 14

Why percentage yield can never be above 100%

Answer 14

Could be because not all of the reactants are used in the reaction

Question 15

How precise results are obtained in a titration

Answer 15

Experimental error is approximately 0.2%