Maths You Need To Know For A-level Chemistry

Below is a short math quiz covering maths topics that are needed for A-level chemistry. The answers to the problems can be found at the end of the article.

Problem 1

The following substances were mixed together: 100 grams of sugar, 250 grams of flour and 50 grams of salt. Please calculate percentage of each substance in the mixture

Problem 2

The mixture is 25% sugar and 75% flour. If I plan to use 10g of sugar, what is the total mass of the mixture that I will prepare?

Problem 3

Please perform the following calculations without a calculator

(a)10-3 x 10 2.5

(b) 10-26/10-35

(c) 10-42 x 1023

Problem 4

Each packet of sugar contains 10g of sugar. If I need 0.25g of sugar, how many packets do I need?

If I have 0.75 packets of sugar, how many grams of sugar do I have?

Problem 5

1 kilogram is equal to 1000 grams. How many grams are in 0.75 kilograms? How many kilograms are in 25 grams?

Problem 6

Please perform the following calculations without a calculator

Log1010-6 =

Log10X = -3 what is the value of X?

Answers:

Problem 1

Total mass: 400 grams

%Sugar: 100/400 x 100 = 25%

%Flour: 250/400 x 100 = 62.5%

%Salt: 50/400 x 100 = 12.5%

Problem 2

10 g of sugar = 25%

X g of flour = 75%

X = (10 x 75)/25 = 30g

Problem 3

When two same numbers with exponents are multiplied, the exponents are added. When numbers are divided, the bottom exponent is subtracted from the top.

10-0.5

109

10-19

Problem 4.

1 packet = 10g

X packet = 0.25g

10x = 0.25

X = 0.25/10 = 0.025 packets

1 packet = 10g

0.75 packet = X grams

X = 10 x 0.75 = 7.5 grams

Problem 5

0.75 kg x 1000g/1kg = 750 g

25g x 1kg/1000 g = 0.025kg

Problem 6

-6

X = 10This resource was uploaded by: Anna