Help with 5 and 6 please? I tried #5 but what I came up with for m and M doesn’t

Question

Help with 5 and 6 please? I tried #5 but what I came up with for m and M doesn’t seem right. Thanks in advance.
5. 91.0% mass isopropyl alcohol(C3H7OH) has a density of .740 g/ml. Calculate the Molarity and morality of this solution.
6. Suppose the concentration of CO2 in a liquid is .00410 M when the pressure of CO2 above the liquid is .053 atm. what would the concentration of CO2 become if the pressure of CO2 above the liquid was raised to 10.5 atm?

91.0% mass isopropyl alcohol (C3H7OH) hasa density of0ZA0 g/mL. Calculate the Molarity and molality of this solution. 5. Mz 1.120 74o, 095 0a1 o13 5.135 6. Suppose the concentranon ofco, in a liquid is 0.00410 M when the pressure of COz above Che 03 liquid is 0.053 atm. What would the concentration of CO2 bcome if the pressure of Co2 a liquid was raised to 10.5 atm? bove the

Explanation / Answer

in answer:

given that we have a solution which contains 91 % mass of isopropyl alcohol that means remaining 9% is fluid (volume).

mass of isopropyl alcohol in solution = 0.91 gram

volume of solution = ?

So, we know density = mass/ volume

0.74 = 0.91/volume => volume = 1.23 ml

volume of solution = 1.23 ml

We know that Molarity = (mole of solute/ volume of solution( Litre)

moles of solute = .91/60 = 0.0151 ( molecular weight = 60)

volume of solution = 1.23 ml

therefore molarity = .(0.0151/ (1.23/1000))

molarity = 12.276 M

and molality = mole of solute / mass of solvent in kg ( mass of solvent = 0.09 grams)

molality = .0151 / 0.00009 = 167.77 m

solute = isopropyl alcohol and solvent = liquid

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2) assume that solution is ideal

we know that ideal gas equation

PV = nRT ( p = pressure, V = volume of gas, n = no. of moles, R = gas constant and T = temperature)

P = nRT/V

P = MRT ( M = molarity = n/V)

So, 1st case P = .053 and M = .0041 M

therefore 0.053 = .0041 *RT ------> (1)

2nd case P = 10.5 and M = ?

10.5 = M*RT ---------> (2)

equation (1)/ (2)

.053/10.5 = 0.0041/M

M (concentration at P = 10.5) = 0.812 M

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