Answer :
According to the law of conservation of mass, the mass of reactants must be equal to the mass of products.
The balanced chemical reaction is,
As we know that the molar mass of magnesium is 24 g/mole, the molar mass of 
is 32 g/mole and the molar mass of magnesium oxide is 40 g/mole.
From the given balanced reaction, we conclude that
As, 1 mole of magnesium react 
mole of oxygen to give 1 mole of magnesium oxide.
So, the mass of Mg is 24 g, the mass of 
and the mass of MgO is 40 g.
That means 24 g of Mg react with 16 g to give 40 g of MgO.
Gay-Lussac's law gives the relationship between pressure and temperature of a gas.
it states that for a fixed amount of gas of constant volume pressure is directly proportional to temperature.
P/T = k
where P - pressure, T - temperature and k - constant
where parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation.
temperature should be in the kelvin scale,
T1 = 22 °C + 273 = 295 K
substituting the values in the equation
T = 492 K
new temperature - 492 - 273 = 219 °C
Convert temperature to Kelvin
Convert vol to L
Apply Charles law
- V1T_2=V2T_1
- 0.4(400)=498V_2
- 160=498V_2
- V_2=0.32L=320mL
