A solution of 5.0 g benzoic acid (C6H5COOH) in 100.0 g of carbon tetrachloride has a boiling point of 77.5° C. The boling point of pure CCl4 is 76.5° C. Calculate the molar mass of benzoic acid in the solution based on the boiling point elevation. (Kb for CCl4 is 5.03° C/m.)

The molar mass of benzoic acid is 251.3 g/mol

Explanation:

∆T = m × Kb

m (molality) = ∆T/Kb = (77.5 - 76.5)/5.03 = 1/5.03 = 0.199 mol/kg

Molar mass of benzoic acid = mass of benzoic acid ÷ (molality × mass of CCl4 in kilograms) = 5 ÷ (0.199 × 100/1000) = 5 ÷ 0.0199 = 251.3 g/mol

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

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sio2 (quartz)