Question

A-- 1.25 cubic inch (in3) sample of glycerol has a mass of 25.2 grams. What is the mass of a 57-mL sample of glycerol?

b---The pressure of the earth's atmosphere at sea level is 14.7 lb/in2 (pounds per square inch). What is the pressure when expressed in g/m2 (grams per square meter)? (2.54 cm = 1 in., 2.205 lb = 1 kg)

c---Solid calcium oxide is reacted with solid carbon to form calcium carbide (CaC₂) and carbon dioxide.

Write a balanced chemical equation that describes this reaction. (3 points)

If the reaction is carried out using 100.00 grams of calcium oxide and 100.00 g of carbon, how many moles of each reactant are used? (2 points)

d---Ammonium sulfate is primarily used as a fertilizer for alkaline solids. In the soil the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth.

What is the chemical formula of ammonium sulfate? (1 point)

What is the mass percentage of nitrogen in ammonium sulfate? (2 points)

How many moles of ions are released when 13.2 g of ammonium sulfate is dissolved in water? (2 points)

Answer 1

A). 1.25 cubic inch (in3) sample of glycerol has a mass of 25.2 grams.

We know that,

1.25 cubic inch = 1.25 * 16.387 mL

= 20.48 mL

So, 20.48 mL sample of glycerol has a mass of 25.2 grams.

Mass of 57 mL glycerol sample = 25.2 * 57 / 20.48

= 70.13 g

(B). Pressure = 14.7 lb/in2

2.205 lb = 1 kg = 1000 g

14.7 lb = 1000 * 14.7 / 2.205

= 6666.67 g

1 in = 2.54 cm = 0.0254 m

1 in2 = 6.45x10^-4  m2

Now,

Pressurein gram/ m2 = 6666.67 g / 6.45x10^-4  m2

= 1.033x10⁷ g/m2

(C). Solid calcium oxide is reacted with solid carbon to form calcium carbide (CaC2) and carbon dioxide.

2CaO(s) + 5C(s)    2CaC2(s) + CO2(g)

100.00 grams of calcium oxide = 100.0 g / 56.077 g/mol

= 1.78 moles

100.00 g of carbon = 100.00 g / 12 g/mol

= 8.33 moles

(D). The chemical formula of ammonium sulfate is -

(NH₄)₂SO₄

Molar mass of ammonium sulfate = 132.14 g/mol

Mass of N in ammonium sulfate = 2*14 = 28 g/mol

Mass percentage of nitrogen = (28 / 132.14) * 100

= 21.18 %

Mass of ammonium sulfate dissolved = 13.2 g

Moles of ammonium sulfate dissolved = 13.2 g / 132.14 g/mol

= 0.01 moles

(NH₄)₂SO₄(aq)    2NH₄⁺(aq)   + SO₄^2-(aq)

1 mole ammonium sulfate produce 3 moles of ions.

0.1 mole ammonium sulfate will release 0.3 moles of ions.