Question

Calculate the mass of magnesium oxide ,when 5.8g of magnesium is burnt in the
presence of air.( atomic mass of Mg = 24and O=16

Answer 1

$\huge \mathscr \pink{Answer}$

Balanced chemical equation

2Mg + O2 -> 2MgO

here , as we can see 2 moles of Mg need 2 moles of MgO

Then 2 moles Mg = 2× 24 = 48g

2 moles 2MgO = 2×40 = 80 g

48g need 80g

24g need 40g

then 2.4 g will need

$\bf\frac{4 \cancel0}{1 \cancel0} = 4g$

There answer equal 4 g