Course home

Calculations involving masses

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117

Question 42

Lithium, sodium and potassium are highly reactive metals in Group 1 of the periodic table.

When a freshly cut piece of potassium metal is exposed to air, it reacts rapidly with oxygen to form a dull layer of potassium oxide on its surface.

In a sample of this oxide, 0.78 g of potassium is combined with 0.16 g of oxygen.

Calculate the empirical formula of this potassium oxide. Relative atomic masses ( $A_r$ ): $O=16\text{O} = 16$ , $K=39\text{K} = 39$

You must show your working.

[3]

Markscheme

Calculations involving masses Questions

GCSE
Chemistry
Calculations involving masses

258 exam-style questions on Edexcel GCSE Chemistry Calculations involving masses. Each one has a worked solution and a mark scheme showing where the marks go.

Calculations involving masses

Question bank

Calculations involving masses

Easy Medium Hard

Question 42

Lithium, sodium and potassium are highly reactive metals in Group 1 of the periodic table.

When a freshly cut piece of potassium metal is exposed to air, it reacts rapidly with oxygen to form a dull layer of potassium oxide on its surface.

In a sample of this oxide, 0.78 g of potassium is combined with 0.16 g of oxygen.

Calculate the empirical formula of this potassium oxide. Relative atomic masses ( $A_r$ ): $O=16\text{O} = 16$ , $K=39\text{K} = 39$

You must show your working.

[3]

Markscheme

Calculations involving masses Questions

GCSE
Chemistry
Calculations involving masses

258 exam-style questions on Edexcel GCSE Chemistry Calculations involving masses. Each one has a worked solution and a mark scheme showing where the marks go.