Answer:
3) an applied electric current
Explanation:
An electric source is used in an electrolytic cell.
The law of conservation of mass dictates that the total mass of reactants must be equal to the total mass of the products. Thus:
mass(MgO) = mass(Mg) + mass(O)
mass(MgO) = 24 + 16
mass(MgO) = 40 g
The third option is correct.
Answer:
2.85moles of oxygen gas
Explanation:
Given parameters:
Volume of oxygen gas = 63.8L
Unknown:
Number of moles = ?
Solution:
We assume that the gas is under standard temperature and pressure. To find the number of moles, use the expression below:
1 mole of a gas at STP occupies a volume of 22.4L
So;
63.8L of oxygen gas will take up a volume of
= 2.85moles of oxygen gas