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3 years ago

Which liquid has the weakest intermolecular forces?

Chemistry

1 answer:

Andreas93 [3]3 years ago

3 0

Answer:

Oil- Only London Dispersion Forces (the weakest intermolecular force)

Water- London Dispersion, Dipole-Dipole, and Hydrogen Bonding

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A 50/50 blend of engine coolant and water (by volume) is usually used in an automobile's engine cooling system. If a car's cooli

iVinArrow [24]

Answer:

108.25 ºC

Explanation:

The boiling point elevation for a given solute in water is given by the expression:

ΔTb = i Kbm

where ΔTb is the boiling point elevation

i is the van´t Hoff factor

Kb the boiling constant which for water is 0.512 ºC/molal

m is the molality of the solution

The molality of the solution is the number of moles per kilogram of solvent. Here we run into a problem since we are not given the identity of the coolant, but a search in the literature tells you that the most typical are ethylene glycol and propylene glycol. The most common is ethylene glycol and this it the one we will using in this question.

Now the i factor in the equation above is 1 for non ionizable compounds such as ethylene glycol.

Our equation is then:

ΔTb = Kbm

So lets calculate the molality and then ΔTb:

m = moles ethylene glycol / Kg solvent

Converting gal to L

4.90 g x 3.785 L/gal = 18.55 L

in a 50/50 blend by volume we have 9.27 L of ethylene glycol, and 9.27 L of water.

We need to convert this 9.27 l of ethylene glycol to grams assuming a solution density of 1 g/cm³

9.27 L x 1000 cm³ / L = 9273.25 cm³

mass ethylene glycol = 9273.25 cm³ x 1 g/cm³ = 9273.25 g

mol ethylene glycol = 9273.25 g/ M.W ethylene glycol

= 9273.25 g / 62.07 g/mol =149.4mol

molality solution = 149.4 mol / 9.27 Kg H₂O = 16.12 m

( density of water 1 kg/L )

Finally we can calculate ΔTb:

ΔTb = Kbm = 0.512 ºC/molal x 16.12 molal = 8.25 ºC

boiling point = 100 º C +8.25 ºC = 108.25 ºC

( You could try to solve for propylene glycol the other popular coolant which should give around 106.7 ºC )

6 0

3 years ago

What is the molar mass of Ca(OH)2?

liubo4ka [24]

Answer: the molar mass is 74.092 g/mol

Explanation:

8 0

3 years ago

Use the Henderson-Hasselbalch equation and your knowledge of ionization to help you answer this question. Aspirin is a weak acid

Leya [2.2K]

Answer:

The protonated form is predominant when aspirin is absorbed more readily. The ratio of conjugate base to acid is 1 to 100.

Explanation:

Aspirin is more readily absorbed when it is protonated, that is when pH is lower than pKa (<em>more H⁺ available in the medium</em>). We can confirm this using Henderson-Hasselbalch equation for pH = 1.5:

$pH = pKa +log(\frac{conjugate base}{weak acid} )\\1.5=3.5 +log(\frac{conjugate base}{weak acid} )\\-2.0=log(\frac{conjugate base}{weak acid} )\\10^{-2.0} =\frac{conjugate base}{weak acid}\\\frac{conjugate base}{weak acid}=0.01=\frac{1}{100}$