A student prepares an alloy by melting together separate samples of magnesium ribbon…

CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance

Problem

A student prepares an alloy by melting together separate samples of magnesium ribbon and aluminum foil. (a) Calculate the amount of substance (in moles) contained in

3.00\,\text{g}

of Mg and in

4.50\,\text{g}

of Al. (Molar masses:

24.31\,\text{g\,mol}^{-1}

for Mg,

26.98\,\text{g\,mol}^{-1}

for Al.) (b) Determine the combined number of metal atoms present in the molten mixture. Report the answer in scientific notation and include appropriate units. (c) Compute the percentage of the total atoms contributed by aluminum and discuss what this reveals about the atomic-level composition of the alloy relative to the mass percentages of the two metals.

Related theory

Alloys and amalgams
Mole concept
Some Basic Concepts of Chemistry
Mole Concept and Molar Masses

Browse the problem library