Question

A scientist wished to carry out a chemical reaction in which two moles of aluminum combine with three moles of sulfur. He has 2.70 g of aluminum to react. How many grams of sulfur must he take to satisfy all the aluminum atoms?

1.51 g
2.14 g
3.41 g
4.81 g

Answer 1

4. (81 g) is the correct answer

Answer 2

Answer : The correct option is, 4.81 g

Explanation : Given,

Mass of aluminium = 2.70 g

Molar mass of aluminium = 26.98 g/mole

Molar mass of sulfur = 32.07 g/mole

First we have to calculate the moles of aluminium.

$\text{Moles of Al}=\frac{\text{Mass of Al}}{\text{Molar mass of Al}}=\frac{2.7g}{26.98g/mole}=0.1mole$

Now we have to calculate the moles of sulfur.

According to the question,

As, 2 moles of aluminium react with 3 moles of sulfur

So, 0.1 mole of aluminium react with $\frac{3}{2}\times 0.1=0.15mole$ of sulfur

Now we have to calculate the mass of sulfur.

$\text{Mass of sulfur}=\text{Moles of sulfur}\times \text{Molar mass of sulfur}$

$\text{Mass of sulfur}=0.15mole\times 32.07g/mole=4.81g$

Therefore, the mass of sulfur he take must be, 4.81 g