Chemistry Past Questions and Answers

Which of the following is used extensively in manufacturing photographic chemicals?

Given that 1 mole of carbon -12 weighs 12.0g, how many atoms are there in 24.0g magnesium? (C = 12, Mg = 24, NA = 6.02 x 10 ²³mol^-1)

What is the concentration, in mol dm ³, of solution is allowed to evaporate the allotrope of sulphur formed is

If sulphur is dissolved in carbon (IV) sulphide and the solution is allowed to evaporate, the allotrope of sulphur formed is

Given that for the reaction. N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = -92kJ. What is the enthalpy of formation of ammonia from its elements?