Question

If you have 72 moles of krb you need moles of pb(NO3) 2 use it all

Answer 1

We need 36 moles of Pb(NO3)2.

Step-by-step explanation:

You can see that in the chemical equation, 1 mol of Pb(NO3)2 reacts with 2 moles of KBr. If we want to know how many moles of Pb(NO3)2 we require, we have to do a rule of three, like this:

`\begin{gathered} 1\text{ mol Pb\lparen NO}_3)_2\rightarrow2\text{ moles KBr} \\ ?\text{ moles Pb\lparen NO}_3)_2\rightarrow72\text{ moles KBr.} \end{gathered}`

And the calculation would be:

`72\text{ moles KBr}\cdot\frac{1\text{ mol Pb\lparen NO}_3)_2}{2\text{ moles KBr}}=36\text{ moles Pb\lparen NO}_3)_2.`