Chemistry Questions

2010-09-16 5:30 pm

Gas Q is a hydrocarbon with a density of 1.75gdm^3 at room conditions. It can decolorize a solution of bromine in an organicsolvent and also acidified potassium permanganate solution.a)Calculate the relative molecular mass ofQ.(hint: the volume of one mole of a gas at room conditions = 24 dm^3mol^-1)b)Deduce the identity of Q.c)Predict, with reasoning, the product expectedwhen Q reacts with hydrogen chloride.

回答 (1)

己式庚辛

2010-09-16 7:53 pm

✔ 最佳答案

assuming there's 24dm^3 of gas Q, then mass of Q = 1.75 x 24 = 42g
no. of mole of Q = 24/24 = 1 mole
relative molecular mass (OR molar mass) = 42/1 = 42 (g/mol)

as Q can decolorize bromine, it's probably an alkene.
empirical formula of Q is CH
let molecular formula of Q to be (CH2)y
molecular mass of Q = (12+1x2)y
42 = 14y
y = 3

so Q is C3H6, probably propene.

addition reaction occurs when HCl is added, giving 2-chloropropane as major product, and 1-chloropropane as minor product.

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