PLEASE SOMEONE HELP!!!! I cannot figure this out! I have the answers, but I need

Question

PLEASE SOMEONE HELP!!!! I cannot figure this out! I have the answers, but I need to know HOW to get them! Please help me.

The compound, AwBxCyDz has an oxidation number of 0 (zero). The oxidation number of A is +1, the oxidation number of B is +2, the oxidation number of C is –3, and the oxidation number of D is 0. The molar mass of C is 500.0 g/mol. Previously determined: Moles of A in 100 grams of the compound: 0.0800 mol A Moles of B in 100 grams of the compound: 0.0200 mol B Calculate the following values:

5. Moles of C in 100 grams of the compound (use oxidation numbers)

6. Mass of C in 100 grams of the compound

7. Mass % of C in the compound

Answers: (5) 0.0400 mol C; (6) 20.0 g C; (7) 20.0% C

Part C. The molar mass of D is 166.7 g/mol. Calculate the following values:

8. Mass % D in the compound

9. Mass of D in 100 grams of the compound

10. Moles of D in 100 grams of the compound

11. Formula of the compound

Answers: (8) 10.0% D; (9) 10.0 g D; (10) 0.0600 mol D; (11) A4BC2D3

Explanation / Answer

Determine the moles of C in 100 grams of compound using oxidation number

(w * +1) + (x * +2) + (y * -3) + (0 * 0) = 0. So

w + 2x -3y = 0

Given that;

0.0800 mol A and 0.0200 mol B ; total moles of A and B = 0.1 moles

The ratio of moles A:B is 4:1, 0.0800/ 0.0200 = 4/1 so perhaps A4B1CyDz represent the formula or a multiple of it, The sum of y and z = 0.9

On this basis and using oxidation numbers (+1 *4) + (1 x +2) + (y * -3) + (0 * z) = 0 giving 4 + 2 - 3y + 0 = 0, so 3y = 6 and y = 2

According to mole ration number of moles of C = 0.04 in 100 grams

And 0.06 mole for D.

6. Mass of C in 100 grams of the compound

The molar mass of C is 500.0 g/mol

Number of moles in 100 g compound = 0.04

Mass of compound C = 0.04 mole* 500.0 g/mol

= 20.0 g.

7. Mass % of C in the compound

Mass of compound C/ total mass*100

20/100*100=20.0%

Answers: (5) 0.0400 mol C; (6) 20.0 g C; (7) 20.0% C

Part C. The molar mass of D is 166.7 g/mol. Calculate the following values:

8. Mass % D in the compound

Mass of compound D/ total mass*100

10/100*100=10.0%

9. Mass of D in 100 grams of the compound

Number of moles in 100 g compound = 0.06

Mass of compound D = 0.06 mole* 166.7 g/mol

= 10.0 g.

10. Moles of D in 100 grams of the compound

0.06

11. Formula of the compound

Moles of A = 0.08

Moles of B = 0.02

Moles of C = 0.04

Moles of A = 0.06

Divide by lowest number to determine the formula:

Moles of A = 0.08/0.02

=4

Moles of B = 0.02/0.02

=1

Moles of C = 0.04/0.02

=2

Moles of D = 0.06/0.02

=3

A4B1C2D3

Answers: (8) 10.0% D; (9) 10.0 g D; (10) 0.0600 mol D; (11) A4BC2D3

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