What is the mass of #4*10^21# platinum atoms?

1 Answer
May 16, 2016

Answer:

The mass of #4xx10^21# atoms Pt is#" ~~# 1 g Pt.

Explanation:

There are two equalities required to answer this question.

#6.022xx10^23 "atoms"##=##1"mol atoms"#

#1"mol Pt"##=##195.084"g Pt"# (molar mass of Pt)

Then carry out the following operations.

Divide the given number of atoms of Pt by the number of atoms of Pt in a mole. Then multiply by the molar mass of Pt.

#4xx10^21cancel"atoms Pt"xx(1cancel"mol Pt")/(6.022xx10^23cancel"atoms Pt")xx(195.084"g Pt")/(1cancel"mol Pt")="1 g Pt"# (rounded to one significant figure)