Question

can you help me please -

Calculate the mass of sulphur dioxide prodeuced by burning 16g of sulphur in an excess of oxygen​

Answer 1

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Given :-

m(g) of Sulfur = 16g 

Molar mass of sulfur: 32 g/mol  ( from periodic table - atomic mass; mass number or 'A' - the greater number) 

Molar Mass of Oxygen: 16 g/mol ( from periodic table from periodic table - atomic mass; Mass Number or 'A' - the greater number.

Formula Used: 

n(mol)= m (g) / M (g/mol) 

Step One: Write the equation  

S + O2 --> SO2 

Step Two: Balance the equation ( this one doesn't need balancing ) 

S + O2 --> SO2 

Step Three: Write the molar ratios (coefficients) 

S + O2 --> SO2 

1     1           1         <---------molar ratio 

Step Four: Find the number of moles of Sulfur (mol) using the formula: 

 n(mol)= m(g) / M (g/mol) 

Substitute 16g in the mass(m) & 32 g/mol in the Molar Mass( g/mol) 

n(mol)= 16 (g) / 32 (g/mol) 

n(mol) = 0.5 mol of Sulfur 

Step Five: Using the molar ratios and the number of moles of Sulfur obtained, cross multiply to find the number of moles of Sulfur dioxide. 

( For future reference we don't use O2 because it is in excess, anything in excess we don't use) 

S  +  O2 → SO2 

1       1           1       <---------Molar Ratio 

0.5               x       <---------Number of Moles 

1 / 0.5 = 1/x 

n ( Sulfur) = n ( sulfur dioxide)  since the Molar Ratio is one to one n( sulfur dioxide) = 0.5 moles 

Step Six: With the given 0.5 moles for Sulfur dioxide calculated, You can find the mass of sulfur dioxide (SO2).

You just have to calculate the Molar Mass of Sulfur and Oxygen by using your periodic table. Formula used: 

 n(mol) = m(g) / M(g/mol) 

Molar Mass Calculations 

M(O) = 16 g/mol

M(S) = 32 g/mol 

M(SO2) = 32 + 16(2) = 32 + 32 = 64 g/mol.  

 

Number of moles of Sulfur dioxide Calculated: 0.5 mol 

Plug in the values in their Corresponding Locations :-

 n(mol) = m(g) / M(g/mol)

0.5(mol) = m(g) / 64 ( g/mol) 

m(g) = 0.5 x 64 

m(g) = 32 g. 

 

FINAL ANSWER : MASS OF SULFUR DIOXIDE = 32 g.