Question

Niven wants to calculate the mass of mgo that is produced by burning of 28.0g of mg. What is the first step in nivens calculation?

Answer 1

Answer: -

The experiment Niven is doing is burning of Mg.

The first step would be finding the molar mass of MgO

Atomic mass of Mg = 24 g

Atomic mass of Oxygen = 16 g

Molar mass of MgO = 24 x 1 + 16 x 1 = 40 g

The balanced chemical equation for this reaction is

2 Mg + O2 -- > 2MgO

From the balanced equation we see that

2 Mg gives 2 MgO

2 x24 g of Mg O gives 2 x 40 g of MgO.

28g of MgO gives $\frac{2 x 40 gram x 28 gram }{2 x 24 gram}$

= 46.66 g of MgO.

Answer 2

Answer:

The first step would be to write the balanced chemical reaction

Explanation:

Given:

Mass of Mg = 28.0 g

The first step is to write down the balanced chemical reaction depicting the stoichiometry

2Mg + O2 → 2MgO

Therefore, 2 moles of Mg produces 2 moles of MgO

i.e. the ratio of Mg:MgO = 1:1

Atomic mass of Mg = 24 g/mol

Moles of Mg reacted = $\frac{28.0 g}{24 g/mol} = 1.167$

This is equal to the moles of MgO produced = 1.167

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

Mass of MgO produced = 1.167 moles * 40 g/mol = 46.7 g