1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Charra [1.4K]
3 years ago
8

The normal freezing point of a certain liquidXis0.4°C, but when5.90gof ureaNH22COare dissolved in450.gofX, it is found that the

solution freezes at−0.5°Cinstead. Use this information to calculate the molal freezing point depression constantKfofX.
Chemistry
1 answer:
mafiozo [28]3 years ago
3 0

Answer:

The molal freezing point depression constant for X is 4.12 °C/m

Explanation:

Apply the colligative property of freezing point depression:

ΔT = Kf . m . i

We assume the X lquid is non electrolytic, so i = 1

ΔT = T° freezing point of solvent pure - T° freezing point of solution

m = molality (moles of solute in 1kg of solvent)

Kf = Cryoscopic constant (the data we were asked for)

ΔT = 0.4° - (- 0.5°) = 0.9°

Let's calculate molality

Molar mass of urea = 60.06 g/m

Moles of urea = mass of urea / molar mass

5.90 g / 60.06 g/m = 0.098 moles

This moles are in 450 g of solvent, prepare a rule of three to find out the moles in 1000 g

450 g ____ 0.098 m

1000 g ____ ( 1000.  0.098)/450 = 0.218 m

0.9° = Kf . 0.218 m . 1

0.9° / 0.218 m = Kf → 4.12 °C/m

You might be interested in
Two children on roller skates stand facing each other. The child on the right puts her arms out and pushes away from her partner
shutvik [7]

Answer:

They both go backward because of force.

Explanation:

The logic behind this answer is that child right and pushes away causing her to go backward meaning her partner is being pushed backwards to.

(Hope this was helpful!)

8 0
2 years ago
What is the mass % of carbon in dimethylsulfoxide?
ziro4ka [17]

Answer:

There is 30.74% of carbon in dimethylsulfoxide

8 0
2 years ago
Perform the calculation and record the answer with the correct number of significant figures.
kotykmax [81]

The question is incomplete, here is the complete question:

A. (6.5-6.10)/3.19

B. (34.123 + 9.60) / (98.7654 - 9.249)

<u>Answer:</u>

<u>For A:</u> The answer becomes 0.1

<u>For B:</u> The answer becomes 0.4884

<u>Explanation:</u>

Significant figures are defined as the figures present in a number that expresses the magnitude of a quantity to a specific degree of accuracy.

Rules for the identification of significant figures:

  • Digits from 1 to 9 are always significant and have infinite number of significant figures.
  • All non-zero numbers are always significant. For example: 664, 6.64 and 66.4 all have three significant figures.
  • All zeros between the integers are always significant. For example: 5018, 5.018 and 50.18 all have four significant figures.
  • All zeros preceding the first integers are never significant. For example: 0.00058 has two significant figures.
  • All zeros after the decimal point are always significant. For example: 2.500, 25.00 and 250.0 all have four significant figures.
  • All zeroes used solely for spacing the decimal point are not significant. For example: 10000 has one significant figure.

<u>Rule applied for addition and subtraction:</u>

The least precise number present after the decimal point determines the number of significant figures in the answer.

<u>Rule applied for multiplication and division:</u>

In case of multiplication and division, the number of significant digits is taken from the value which has least precise significant digits

  • <u>For A:</u> (6.5-6.10)/3.19

This a a problem of subtraction and division.

First, the subtraction is carried out.

\Rightarow \frac{6.5-6.10}{3.19}=\frac{0.4}{3.19}

Here, the least precise number after decimal was 1.

\Rightarrow \frac{0.4}{3.19}=0.125

Here, the least precise number of significant digit is 1. So, the answer becomes 0.1

  • <u>For B:</u> (34.123 + 9.60) / (98.7654 - 9.249)

This a a problem of subtraction, addition and division.

First, the subtraction and addition is carried out.

\Rightarow \frac{34.123+9.60}{98.7654-9.249}=\frac{43.723}{89.5164}=\frac{43.72}{89.516}

Here, the least precise number after decimal in addition are 2 and in subtraction are 3

\Rightarrow \frac{43.72}{89.516}=0.48840

Here, the least precise number of significant digit are 4. So, the answer becomes 0.4884

6 0
3 years ago
I NEED HELP WITH #3 pleaseeee
Anit [1.1K]

Answer:

energy level

sub energy level

electrons in the orbital

Explanation:

3 0
3 years ago
What is the major underlying principle of chromatography?.
KatRina [158]
Separation will be achieved if one component adheres to the stationary phase more than the other component does.
6 0
2 years ago
Read 2 more answers
Other questions:
  • Identify the product of radioactive decay and classify the given nuclear reactions accordingly.
    6·2 answers
  • Which type of telescope would perform better on a mountaintop than at a lower elevation?
    13·1 answer
  • You are writing a report on whether global warming really exists. Which of the following resources would be the most scientifica
    5·1 answer
  • Whose personal story did you read (if you read several, pick your favorite)? What was the most interesting or eye-opening part o
    7·1 answer
  • Dinitrogen monoxide gas decomposes to form nitrogen gas and oxygen gas. How many grams of oxygen are formed when 10.0 g of dinit
    15·1 answer
  • WILL MARK BRAINLIEST!! URGENT CORRECT ANSWERS NEEDED
    7·1 answer
  • Sulfuric acid (H2SO4) is a very strong diprotic acid. If 0.054 moles of sulfuric acid is mixed with water to make 667 milliliter
    7·2 answers
  • Heptane and water do not mix, and heptane has a lower density (0.684 g/mL.) than water (1.00 g/
    6·1 answer
  • Gases Test<br> Chemistry
    5·1 answer
  • What do you call the things in an experiment that must be the same to make it fair​
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!