A speed-time graph shows a line sloping downward. How was the speed changing?

When of alanine are dissolved in of a certain mystery liquid , the freezing point of the solution is less than the freezing poin

LenaWriter [7]

The question is incomplete, the complete question is:

When 177. g of alanine $(C_3H_7NO_2)$ are dissolved in 800.0 g of a certain mystery liquid X, the freezing point of the solution is $5.9^oC$ lower than the freezing point of pure X. On the other hand, when 177.0 g of potassium bromide are dissolved in the same mass of X, the freezing point of the solution is $7.2^oC$ lower than the freezing point of pure X. Calculate the van't Hoff factor for potassium bromide in X.

<u>Answer:</u> The van't Hoff factor for potassium bromide in X is 1.63

<u>Explanation:</u>

Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.

The expression for the calculation of depression in freezing point is:

$\Delta T_f=i\times K_f\times m$

OR

$\Delta T_f=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}$ ......(1)

<u>When alanine is dissolved in mystery liquid X:</u>

$\Delta T_f=5.9^oC$

i = Vant Hoff factor = 1 (for non-electrolytes)

$K_f$ = freezing point depression constant

$m_{solute}$ = Given mass of solute (alanine) = 177. g

$M_{solute}$ = Molar mass of solute (alanine) = 89 g/mol

$w_{solvent}$ = Mass of solvent = 800.0 g

Putting values in equation 1, we get:

$5.9=1\times K_f\times \frac{177\times 1000}{89\times 800}\\\\K_f=\frac{5.9\times 89\times 800}{1\times 177\times 1000}\\\\K_f=2.37^oC/m$

<u>When KBr is dissolved in mystery liquid X:</u>

$\Delta T_f=7.2^oC$

i = Vant Hoff factor = ?

$K_f$ = freezing point depression constant = $2.37^oC/m$

$m_{solute}$ = Given mass of solute (KBr) = 177. g

$M_{solute}$ = Molar mass of solute (KBr) = 119 g/mol

$w_{solvent}$ = Mass of solvent = 800.0 g

Putting values in equation 1, we get:

$7.2=i\times 2.37\times \frac{177\times 1000}{119\times 800}\\\\i=\frac{7.2\times 119\times 800}{2.37\times 177\times 1000}\\\\i=1.63$

Hence, the van't Hoff factor for potassium bromide in X is 1.63

7 0

3 years ago

PLEASE HELP FAST!!!! Which of the following is NOT an intensive physical property?

Zarrin [17]

Volume is an extensive physical property and not an intensive one.

7 0

3 years ago

Read 2 more answers

you have 150.0 ml of a 0.807 m solution of ce(no₃)₄. what mass (in grams) of ce(no₃)₄ would be required to make the solution?

Hitman42 [59]

The mass of Ce(NO3)₄ that will be needed to create the solution was 24.16 g (in grams).

<h3>What exactly is the solution?</h3>

A homogenous mixture with one or even more solutes that have been dissolved in the solvent is known as a solution. The material that a solute dissolves in to create a homogenous mixture is known as a solvent. To create a homogenous mixture, a component must dissolve in a solvent.

<h3>What is an illustration of a solution?</h3>

One nanometer or smaller particles are referred to as a solution in a homogeneous mixture made up of two or more components. There are many different types of solutions, including sugar and salt solutions and fizzy water. Each component shows up as a different phase in a solution.

<h3>Briefing:</h3>

Mole of Ce(NO₃)₄ = 0.06225 mole

Molar of Ce(NO₃)₄ = 140.12 + 4[14 + (16×3)]

= 140.12 + 4[14 + 48]

= 140.12 + 4[62]

= 140.12 + 248

= 388.12 g/mol

Mass of Ce(NO₃)₄ = 0.06225 × 388.12

Mass of Ce(NO₃)₄ = 24.16 g

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4 0

1 year ago

Can you answer with working out

amm1812

This is your answer I hope it is right.

6 0

3 years ago

Which of the following has the greatest mass for one mole of the compound?

ddd [48]

I think it would be c

3 0

3 years ago