Question

A substance is 89.2% carbon by mass. how much of the substance would be needed to recover 34.6 mol of pure carbon?

Answer 1

1 mole of carbon contains 12 g
Thus, 34.6 moles will contain; 34.6 × 12 = 415.2 g
If a substance contains 89.2 % carbon, 
then, (415.2/89.2) ×100 =  465.47 g of the substance will be required to yield 34.6 moles of carbon.

Answer 2

Answer:

The amount of substance we need to recover 34.6 mol of carbon is 465.47g

Explanation:

we want to know what mass of substance we need to recover 34.6 mol of carbon

This substance is composed of 89.2% carbon

Wmust recover 34.6 mol of carbon and we know that the molecular mass of carbon is 12g / mol this means that one mole of carbon has a mass of 12 g

We use a simple rule of three to know how many grams of carbon are in 34.6 mol

$1 mol C\longrightarrow 12g\\34.6 mol C\longrightarrow x\\x=\frac{(34.6)(12)}{1}= 415.2 g$

415.2 g are 34.6 mol of carbon

As the amount of carbon we want to recover is 415.2g (34.6mol)  and this amount corresponds to 89.2% of the total

To calculate the total mass we need we use a simple rule of three

$89.2\%\longrightarrow 415.2 g\\100\%\longrightarrow x\\x=\frac{(100)(415.2)}{89.2}\\ x= 465.4g$

The amount of substance we need to recover 34.6 mol of carbon is 465.47g