A 25.0 g sample of an aluminum/mercury amalgam used for filling cavities is 7.00% mercury by mass. What is the mass of aluminum in the 25.0 g sample? (Use correct numbers of significant figures)
1 Answer
Explanation:
The problem tells you that the sample is
That is the case because the amalgam contains two elements, aluminium and mercury, and so their respective percent concentration by mass must add up to give
Now, a compound's percent composition tells you how many grams of each of its constituent elements you get for every
In your case, you know that you get
#25.0 color(red)(cancel(color(black)("g amalgam"))) * "93.00 g Al"/(100color(red)(cancel(color(black)("g amalgam")))) = "23.25 g Al"#
Rounded to three sig figs, the answer will be
#color(green)(bar(ul(|color(white)(a/a)color(black)("mass of Al " = " 23.3 g")color(white)(a/a)|)))#