An solution of antifreeze is prepared by mixing 320ml of...

An antifreeze solution is prepared by mixing 32.0 mL of ethylene glycol (d = 1.11 g/mL; molar mass = 62.07 g/mol) with 50.0 mL of H2O (d = 1.00 g/mL) at 25°C. If the density of the antifreeze solution is 1.07 g/mL, what is its molarity?

Transcript

00:01 We know that density is equal to mass divided by volume.

00:07 Now here for ethylene glycol, first of all, we have been given that ethylene glycol is dissolved into water to make the solution.

00:19 So here, ethylene glycol is the solute and water is the solvent.

00:24 So the mass of ethylene glycol, let me write it as e, okay m e so the mass for ethylene glycol will be given by density for ethylene glycol multiplied by volume for ethylene glycol so that will be equal to density is given to us and that is 1 .11 gram per milliliter multiplying volume is also given to us and that is 32 milliliter so that will be 35 .52 grams.

01:10 So this is the mass of ethylene glycol.

01:14 Now here we have also been given the molar mass for ethylene glycol.

01:19 So let me write it as capital m, subscript e.

01:23 So this will be molar mass here we have is 62 .07 gram per mole.

01:33 So with the help of that i can solve for the number of moles of ethylene glycol.

01:38 Number of moles of ethylene glycol will be equal to mass of ethylene glycol divided by molar mass of ethylene glycol.

01:46 This is how we solved for the number of moles.

01:49 So this will be 35 .52 divided by 62 .07.

01:57 So this will be equal to 0 .572.

02:03 So these are the number of moles.

02:06 Now here we can also solve for the mass of water similarly like density of water multiplied volume of water.

02:22 Density of water is 1 gram per milliliter.

02:26 Volume of water is 50 milliliter.

02:31 So this will be 50 grams.

02:36 So now i have mass of ethanol and i have mass of water.

02:40 That is i have mass of solute and mass of solvent so now whenever a solution forms so this form because of the solute and solvent so by adding the masses we can find out the mass for solution so mass for solution so let me write it as ms okay so this is the mass of solution that will be given by mass of ethanol plus mass of water.

03:13 Mass of ethanol is 35 .52 gram and mass of water is 50 gram.

03:21 So this will be after adding 85 .52 gram.

03:31 So this is the mass of solution we have.

03:35 Now here with the help of this mass of solution we can calculate for the volume of solution...

Question

An antifreeze solution is prepared by mixing 32.0 mL of ethylene glycol (d = 1.11 g/mL; molar mass = 62.07 g/mol) with 50.0 mL of H2O (d = 1.00 g/mL) at 25°C. If the density of the antifreeze solution is 1.07 g/mL, what is its molarity?

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