Question

How many grams of oxygen would we need to consume to produce 13.9 grams of MgO​

Answer 1

5.56g

Step-by-step explanation:

Expression of the equation:

2Mg + O₂ → 2MgO

Mass of MgO = 13.9g

Solution:

2Mg + O₂ → 2MgO

To solve this problem, let us find the number of moles of MgO from the given mas;

Number of moles =
`(mass)/(molar mass)`

molar mass of MgO = 24 + 16 = 40g/mol

Number of moles =
`(13.9)/(40)` = 0.35mole

Now,

2 moles of MgO is produced from 1 mole of oxygen gas

0.35 mole of MgO will be produced from
`(0.35)/(2)` mole of oxygen gas

= 0.17mole of oxygen gas

So;

Mass of oxygen gas = number of moles x molar mass

Molar mass of O₂ = 2(16) = 32g/mol

Mass of oxygen gas = 0.17 x 32 = 5.56g