Question

0 g of magnesium is burnt with 0.56 g o2 in a closed vessel

Answer 1

Answer:

The equation is as follows:

2Mg + O2 ------> 2MgO

(s) (g) (s)

Therefore 2 moles of Mg require 1 mole of O2 to produce 2 moles of MgO.

Calculate actual moles.

moles= mass/ molar mass

Mg= 1/24 = 0.041667

O2= 0.56/32 = 0.0175

MgO=

Mole ratio of Mg: O2 = 2:1

find mass of Mg that reacts:

that means 2 mole of Mg reacts with 1 moles of O2

If 1 = 2

Then 0.0175 = 0.0175 x 2

=0.035 moles of magnesium

mass of magnesium that reacts:

mass= moles x molar mass

= 24 x 0.035

0.84 g

That means that of the 1 gram of magnesium that reacts only 0.84 grams is used

Therefore magnesium is in excess and by 0.16

Answer 2

Answer:

The equation is as follows:

2Mg + O2 ------> 2MgO

(s) (g) (s)

Therefore 2 moles of Mg require 1 mole of O2 to produce 2 moles of MgO.

Calculate actual moles.

moles= mass/ molar mass

Mg= 1/24 = 0.041667

O2= 0.56/32 = 0.0175

MgO=

Mole ratio of Mg: O2 = 2:1

find mass of Mg that reacts:

that means 2 mole of Mg reacts with 1 moles of O2

If 1 = 2

Then 0.0175 = 0.0175 x 2

=0.035 moles of magnesium

mass of magnesium that reacts:

mass= moles x molar mass

= 24 x 0.035

0.84 g

That means that of the 1 gram of magnesium that reacts only 0.84 grams is used

Therefore magnesium is in excess and by 0.16