Question

# Calculate the number of moles of sulfur atoms present in each of the following samples. (a)...

Calculate the number of moles of sulfur atoms present in each of the following samples.

(a) 2.16 g of sodium sulfate
(b) 2.16 g of sodium sulfite
(c) 2.16 g of sodium sulfide
(d) 2.16 g of sodium thiosulfate, Na2S2O3

2-
Calculate the percent by mass of each element in the following compounds.

(c) MnO2

 manganese % oxygen %

(a) 2.16 g of sodium sulfate Na2SO4 = 142.04

mol Na2SO4 = mass/MW = 2.16/142.04 = 0.015206

mol of S = 1*0.015206 = 0.015206 mol of S

(b) 2.16 g of sodium sulfite Na2SO3 = 126.043

mol Na2SO3 = mass/MW = 2.16/126.043 = 0.01713

mol of S = 1*0.01713= 0.01713 mol of S

(c) 2.16 g of sodium sulfide Na2S = 78.0452

mol Na2S = mass/MW = 2.16/78.0452 = 0.02767

mol of S = 1*0.02767= 0.02767mol of S

(d) 2.16 g of sodium thiosulfate, Na2S2O3 = 158.11

mol Na2S = mass/MW = 2.16/158.11 = 0.01366

mol of S = 2*0.01366= 0.02732 mol of S

2.

Mn = 54.938045

Oxygen = 16

total mas s= 54.938045 +16*2 = 86.938045

% Mn = 54.938045/86.938045*100 = 63.1921%

% O = 16*2/86.938045*100 = 36.8078 %

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