A student receives a heterogeneous mixture that is known to contain only crystalline…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A student receives a heterogeneous mixture that is known to contain only crystalline sodium chloride and insoluble silica sand. The student quantitatively transfers a 4.85 g portion of the mixture to a beaker, adds distilled water, stirs thoroughly, filters the mixture, and dries both the recovered sand and the filtrate.
The dried sand weighs 1.42 g. Evaporation of the filtrate to dryness leaves 3.39 g of solid sodium chloride.
Respond to the tasks below, showing all reasoning and including appropriate units.
(a) Verify that the mass data are self-consistent with the original sample mass.
(b) Calculate the mass percent of sodium chloride and the mass percent of silica sand in the original mixture.
(c) Express the mass fraction of silica sand as a decimal with four significant figures.