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A. 8.8 g.

B. 5.3 g.

C. 449 g.

Explanation:

A. Determination of the mass of CO2.

Mole of CO2 = 0.2 mole

Molar mass of CO2 = 12 + (2×16)

= 12 + 32

= 44 g/mol

Mass of CO2 =?

Mole = mass /Molar mass

0.2 = mass of CO2 /44

Cross multiply

Mass of CO2 = 0.2 × 44

Mass of CO2 = 8.8 g

B. Determination of the mass of Na2CO3.

Mole of Na2CO3 = 0.05 mole

Molar mass of Na2CO3 = (2×23) + 12 + (3×16)

= 46 + 12 + 48

= 106 g/mol

Mass of Na2CO3 =?

Mole = mass /Molar mass

0.05 = mass of Na2CO3 /106

Cross multiply

Mass of Na2CO3 = 0.05 × 106

Mass of Na2CO3 = 5.3 g

C. Determination of the mass of Fe(OH)2.

Mole of Fe(OH)2 = 5 moles

Molar mass of Fe(OH)2 = 55.8 + 2(16 + 1)

= 55.8 + 2(17)

= 55.8 + 34

= 89.8 g/mol

Mass of Fe(OH)2 =?

Mole = mass /Molar mass

5 = mass of Fe(OH)2/89.8

Cross multiply

Mass of Fe(OH)2 = 5 × 89.9

Mass of Fe(OH)2 = 449 g.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.