Mark asks…
Chlorocyclohexane + Mg in diethyl ether can be what kind of reaction?
We’ve been studying alkanes alkenes and alkynes but so far I haven’t seen a reaction with Mg and diethyl ether. What kind of alkane reaction can that be?
weight loss cardiff answers:
This is a Grignard reaction to form the Grignard reagent cyclohexylmagnesium chloride. Grignard reactions are reactions between halogenoalkanes/arenes and magnesium to form Grignard reagents which are nucleophiles and are used in synthesis to add alkyl/aryl groups to a compound.
Ruth asks…
What is the heat required to vaporize 80.0 g of liquid diethyl ether, (C2H5)2O, at its boiling point?
The ΔH° of vaporization of diethyl ether is 26.0 kJ/mol. Use a molar mass with at least as many significant figures as the data given.
weight loss cardiff answers:
Know: MM=74.12 g/mol (C2H5)O2
want: x kJ
step 1: start with g, go to mol, go to kJ
step 2: check ans
80 g x(mol/74.12 g) x(26 kJ/mol)=28.1 kJ
Nancy asks…
What is the density of Diethyl Ether?
Diethyl ether, (C2H5)2O, vaporizes easily at room temperature. If the vapor exerts a pressure of 233mm Hg in a flask at 25’C, what is the density of the vapor?
weight loss cardiff answers:
Density = mass/volume
Since mass is the number of moles (n) * molar mass (M), density = nM/V
According to the ideal gas law, PV = nRT. Therefore, n = PV/RT
Plug that in for n in the density equation to get
density = PVM/(RTV)
The V’s cancel, so the final equation for density is
density = PM/RT
Convert the vapor pressure of 233 mmHg to 1 atm (1 atm = 760 mmHg), convert the temperature from Celsius to Kelvin (Celcius + 273 = Kelvin), and use R = 0.0821 L*atm / (mol*K). Find molar mass of diethyl ether
C = 12.01 x 4 = 48.04g
H = 1.01 x 10 = 10.10g
O = 16.00 x 1 = 16.00g
molar mass M = 74.14g/mol
density = (233 mmHg * 1 atm / 760 mmHg) * 74.14g/mol / (298 K * 0.0821) = 0.93 g/L
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