Question

For an alloy that consists of 91.0 g copper, 111 g zinc, and 7.51 g lead, what are the concentrations (a) of Cu (in at%), (b) of Zn (in at%), and (c) of Pb (in at%)

Answer 1

`\% Cu=45.2\%\\\\\% Zn=53.6\%\\\\\% Pb=1.2\%`

Step-by-step explanation:

Hello!

In this case, given the masses of copper, zinc and lead, it is possible to compute the moles via their atomic masses first:

`n_(Cu)=(91.0gCu)/(63.55g/mol)=1.432mol\\\\ n_(Zn)=(111gZn)/(65.41g/mol)=1.697mol\\\\n_(Pb)=(7.51gPb)/(207.2g/mol)=0.0362mol\\`

Now, we compute the atomic percentages as shown below:

`\% Cu=(1.432)/(1.432+1.697+0.0362)*100\% =45.2\%\\\\\% Zn=(1.697)/(1.432+1.697+0.0362)*100\%=53.6\%\\\\\% Pb=(0.0362)/(1.432+1.697+0.0362)*100\%=1.2\%`

Best regards!