Chemistry calculations (O level) This post is about answering O level chemistry calculations questions which are part of stoichiometry. To fully understand these calculations you should be familiar with: how to use the periodic table relative molecular mass molar mass moles concentration valency These questions are compatible with Zimsec O level Chemistry and Combined science. …
Stoichiometry Questions and Answers(Page 2) Question 1 Sodium sulphate has the following composition by mass: sodium 32.4%, sulphur 22.5% and oxygen 45.1%. What is its empirical formula? Solution 1 Sodium Sulphur Oxygen Mass 32.4 22.5 45.1 Moles 32.4/23 22.5/32 45.1/16 = 1.41 = 0.7 = 2.82 Molar Ratio 1.41/0.7 0.7/0.7 2.82/0.7 = 2 = 1 …
Stoichiometry Questions and Answers (Page 1) Use the values of Ar which follow to answer the questions below. [H = 1; C = 12; N = 14; O = 16; Ne = 20; Na = 23; Mg = 24; S = 32; K = 39; Fe = 56; Cu = 63.5; Zn = 65. ] …