Q. 7.59

Question

Sodium reacts with oxygen to produce sodium oxide.

a. How many grams of Na2O are produced when 57.5g of Na reacts?

b. If you have 18.0g of Na, how many grams of O2 are needed for the reaction?

c. How many grams of O2 are needed in a reaction that produces 75.0g of Na2O?

Step-by-Step Solution

Verified
Answer

a. 77.5g of Na2O produced from the reaction.

b. 6.24g of O2 is required for the reaction.

c. 19.35g or O2 is required for the reaction.

1Part (a) Step 1: Given Information

We need to find the grams of Na2O which produced when 57.5g of Na reacts.

2Part (a) Step 2: Calculation

The mole factor is given as

mole factor=2moleNa2O4moleNa

We know that

mass of Na=57.5g,

molar mass of Na=23g/mole

so,

mole of Na=massmolar mass=57.5g23g/mole=2.5mole

We have

4 mole of Na=2 mole of Na2O2.5moleNa×2moleNa2O4moleNa=1.25mole Na2O

Now,

Mass of Na2O=molar mass×mole=62gmole×1.25moleMass of Na2O=77.5g

3Part (b) Step 1: Given Information

We need to find how many grams of O2 required to react with 18.0g of Na.

4Part (b) Step 2: Calculation

The mole factor is given as

mole factor=1moleO24moleNa

We have

mass of Na=18g,

molar mass of Na=23g/mole

mole of Na=massmolar mass=18g23g/mole=0.78mole

4 mole Na=1 mole O20.78 mole Na×1moleO24moleNa=0.195mole O2

Now,

mass of O2=molar mass×mole=32gmole×0.195molemass of O2=6.24g

5Part (c) Step 1: Given Information

We need to find the grams of O2 require for the reaction to produce 75.0g of Na2O.

6Part (c) Step 2: Calculation

The mole factor is given as

mole factor=1mole O22mole Na2O

We have

mass of Na2O=75.0g,

molar mass of Na2O=62g/mole

So,

mole of Na2O=massmolar mass=75g62g/molemole of Na2O=1.21mole

also we have

2mole Na2O=1 mole O2

so,

1.21mole Na2O×1 moleO22moleNa2O=0.604mole O2

Now,

mass of O2=molar mass×mole=32gmole×0.604molemass of O2=19.35g