I need help with C and D please! The queen, Snow White\'s wicked stepmother, bei

Question

I need help with C and D please! The queen, Snow White's wicked stepmother, being frosted by her mirror's most recent reply to her favorite question, decides to frost her mirror using hydrofluoric acid according to the following reaction: HF + SiO_2 rightarrow SiF_4 + H_2O If 300 grams of HF are used up in the process, what volume of SiF_4 is produced? Meanwhile in the forest with the dwarves The depletion of their magnesium mine has changed their mood from one of Hi-Ho to one of Ho-Hum. An exhausting search has turned up two additional sources of magnesium: one containing the ore MgO and the other the ore MgF_2 Grumpy, their resident chemist, runs a percent composition analysis on the two ores to determine which will be the richest source of Mg. Which one will he decide upon? Help defend his choice. The queen decides to make a potion with which to inject an apple and eliminate her competition. One of the ingredients necessary is Al_2(SO_4)_3. A quick inspection of her chemical cabinet shows this to be unavailable, but it can be made from Al(OH)_3 and H_3SO_4 according to the reaction: 2 Al(OH)_3 + 3H_2SO_4 rightarrow Al_2(SO_4)_3 + 6H_2O If 3.42 grams of Al_2(SO_4)_3 are required, what mass of H_2SO_4 must be present? Snow White's stepmother transports herself to the forest on a gigantic thunderbolt It was estimated by a group of very frightened moles that 6000 liters of ozone were formed in the process. How many liters of oxygen were converted? O_1 rightarrow O_3 Snow White if found in a heap on the ground, an apple with one bite from it by her side. Grumpy deduces

Explanation / Answer

c)

2Al (OH)3 + 3H2SO4 ----> Al2(SO4)3 + 6H2O

Step 1- Convert g into mole

3.42 g of Al2 (SO4)3

Molar mass of Al2 (SO4)3 = 342.15 g/mol

Moles ofAl2 (SO4)3 = 3.42 g of Al2 (SO4)3/ 342.15 g/mol = 0.01 moles

Step2- Calculate moles of H2SO4 are needed -

Reaction stoichiometry shows-

For producing 1 moles of Al2 (SO4)3, 3 moles of H2SO4 are needed

So for producing 0.02 moles of Al2 (SO4)3, 0.02 x (3 ) = 0.06 moles of H2SO4 are needed

Step 3- Convert moles of H2SO4 into g

Molar mass of H2SO4 = 98.079 g/mol'

Mass of H2SO4 = Molar mass of H2SO4 x moles of H2SO4

Mass of H2SO4 = 98.079 g/mol x 0.06 moles = 5.88g

d)

3 O2 (g) = 2 O 3(g)

Step1- Calculate moles of O3

Avogadro law states that 1 mol of any gas occupies 22.4 liters

So 6000L of O3 contains 6000/22.4 = 267.857 moles O3

Step2- Calculate moles of O2

Reaction stoichiometry shows-

2 moles of O3 are formed from 3 moles of O2

So 267.857 moles O3 are formed from 267.857 x (3/2) moles of O2

= 401.785 moles of O2

Step 3- Convert moles of O2 into L of O2

1 mol of any gas occupies 22.4 liters

So, 401.785 moles of O2 occupy 22.4 liters x 401.785 = 8999.98L of O2

(Another simple way to calculate volume of O2 is to first calculate molar ratio of O2: O3 = 3:2. Avogadro law states that 1 mol of any gas occupies 22.4 liters, so their volume ratio is same.

O2: O3 = 3:2 = x: 6000L

X = 9000L

Volume of O2 = 9000L)

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