1- The compound para-dichlorobenzene is used in mothballs. Its analysis is 49.02

ID: 794791 • Letter: 1

Question

1- The compound para-dichlorobenzene is used in mothballs. Its analysis is 49.02% C, 2.74% H,

and 48.24% Cl. Its molar mass is 147.0 g/mol. What is its empirical formula and its molecular

formula?

2. Fructose, sometimes called fruit sugar, is 40.0% C, 6.7% H and 53.3% O. Its molar mass is

180.2 g/mol. Determine the empirical and molecular formulas for fructose.

3. Identify the solute in each of the solutions:

a) 2g sugar in 100 mL water _____________________

b) 60.0 mL ethyl alcohol and 30.0 mL of methyl alcohol _____________________

c) 55.0 mL water and 1.50g sodium chloride _____________________

d) 300 mL O2 and 800 mL N2 _____________________

1) c in the compound = 0.4902*147 = 72.59 g

=> moles of carbon in the compound = 72.6/12 = 6 moles.

weight of H = 0.0274*147 = 4.0278 g.

moles of H = 4.02/1 = 4 moles.

weight of Cl = 147*0.4824 = 71 g

moles of Cl = 71/ 35.5 = 2 moles.

so the compound is C6H4Cl2 .

so empirical formula is C3H2Cl.

2) weight of carbon = 0.4*180.2 = 72.08 g

moles of carbon = 72/12 = 6 moles.

weight of hydrogen = 0.067*180.2 = 12.07.

moles of hydrogen = 12/1 = 12moles.

weight of O = 0.533*180.2 = 96.0466.

moles of oxygen = 96/16 = 6 moles.

so the compound is C6H12O6.

empirical form is CH2O.

a) sugar is the solute.

b)methyl alcohol is the solute as it has low volume.

c) sodium chloride is the solute.

d)O2 is the solute.

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