Magnesium nitrate hexahydrate has the formula Mg(NO₃)₂·6H₂O
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
Magnesium nitrate hexahydrate has the formula Mg(NO₃)₂·6H₂O. Atomic masses (g mol⁻¹): Mg = 24.31, N = 14.01, O = 16.00, H = 1.008.
(a) Calculate the mass percent of each of the following in Mg(NO₃)₂·6H₂O. Show every step clearly.
(i) Magnesium
(ii) Nitrogen
(iii) Oxygen that is part of the nitrate ions
(iv) Water of crystallization
(b) A sealed vial contains 15.0 g of Mg(NO₃)₂·6H₂O. Determine the mass of water that could be driven off if the hydrate is heated to constant mass.
(c) How many moles of water are present in the 15.0 g sample? Express the answer with the correct number of significant figures.