Part A:

A mixture of carbon and sulfur has a mass of 9.0 g. Complete combustion with excess O2 gives 27.1 g of a mixture of CO2 and SO2.

Find the mass of sulfur in the original mixture.

Part B:

Calculate the mass, in grams, of a single silver atom (mAg = 107.87 amu ).

Part A = The mass of sulfur is 6.228 grams

Part B = The mass of 1 silver atom is 1.79 * 10^-22 grams

Explanation:

Part A

Step 1: Data given

A mixture of carbon and sulfur has a mass of 9.0 g

Mass of the product = 27.1 grams

X = mass carbon

Y = mass sulfur

x + y = 9.0  grams

x = 9.0 - y

x(molar mass CO2/atomic mass C) + y(molar mass SO2/atomic mass S) = 22.6

(9 - y)*(44.01/12.01) + y(64.07/32.07)

(9-y)(3.664) + y(1.998)

32.976 - 3.664y + 1.998y = 22.6

-1.666y = -10.376

y = 6.228 = mass sulfur

x = 9.0 - 6.228 = 2.772 grams = mass C

The mass of sulfur is 6.228 grams

Part B

Calculate the mass, in grams, of a single silver atom (mAg = 107.87 amu ).

Calculate moles of 1 silver atom

Moles = 1/ 6.022*10^23

Moles = 1.66*10^-24 moles

Mass = moles * molar mass

Mass = 1.66*10 ^-24 moles *107.87

Mass = 1.79 * 10^-22 grams

The mass of 1 silver atom is 1.79 * 10^-22 grams

Explanation:

This is like an empirical formula question, except that you are finding the molar ratio of compounds instead of atoms.

Step 1. Gather the information in one place.

M_r:                                            142             18

           Na₂SO₄·xH₂O(s) ⟶ Na₂SO₄(s) + xH₂O(g)

m/g:              3.22                      1.42

Step 2. Calculate the mass of the water

Mass of H₂O = mass of Na₂SO₄·xH₂O – mass of Na₂SO₄

= 3.22 – 1.42 = 1.80 g

Step 3. Calculate the moles of each product

Na₂SO₄:

     H₂O:

Step 4. Calculate the molar ratios

, so the formula of the compound is Na₂SO₄·10H₂O