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
Leviafan [203]
3 years ago
9

A certain substance X has a normal boiling point of 124.2 °C and a molal boiling point elevation constant K,-06-0C-kg-mol ·A sol

ution is prepared by dissolving some urea ((N112)CO) in 650. g ofl. This solution boils at 124.7 oC, Calculate the mass of urea that was dissolved. Be sure your answer has the correct number of significant digits. 31.48 g
Chemistry
1 answer:
Mashutka [201]3 years ago
8 0

Answer:

32 g

Explanation:

The increase in the boiling point of X can be calculated using the following expression.

ΔT = Kb × b

where,

ΔT: increase in the boiling point

Kb: molal boiling point constant (0.62 °C.kg/mol) (I looked it on the web)

b: molality of the solute

ΔT = Kb × b

(124.7°C - 124.2°C) = (0.62 °C.kg/mol) × b

b = 0.81 mol/kg

The mass of X is 650 g (0.650 kg). Then, the moles of urea (solute) are:

\frac{0.81molUrea}{1kgX} .0.650kgX=0.53molUrea

The molar mass of urea is 60.06 g/mol. The mass of urea is:

0.53mol.\frac{60.06g}{mol} =32g

You might be interested in
NEED QUICK ANSWERS ( science)
nata0808 [166]

Answer:

Explanation:

"Nature does this job through a process called the water cycle. Also known as hydrologic cycle, the water cycle is a phenomenon where water moves through the three phases (gas, liquid and solid) over the four spheres (atmosphere, lithosphere, hydrosphere and biosphere) and completes a full cycle. The water cycle has many effects: it regulates the temperature of the surroundings. It changes weather and creates rain. It helps in conversion of rocks to soil. It circulates important minerals through the spheres. It also creates the many geographical features present on earth like the ice caps of mountains, icebergs, the rivers and the valleys, lakes, and more. Hence it is quite important to understand and learn the processes of the water cycle."

-Water cycle a guide for students.

6 0
3 years ago
A student has the following data: V1 = 822 mL; T1 = 75.0 °C; T2 = 25.0 °C. She uses this data to calculate V1 and gets -274 mL.
luda_lava [24]
Answer to this question is C. Regarding the volume.
4 0
4 years ago
Which phrase describes air density?
saw5 [17]

Answer:B equals mass divided by volume

Explanation:I got hacks :)

7 0
3 years ago
Read 2 more answers
Water is a pure substance. Which of the following is true about water? (4 points) Its compounds can only be physically separated
jonny [76]

Answer:

Water/H20 is a compound made of hydrogen and oxygen. Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water.

Explanation:

7 0
3 years ago
Describe the difference between accuracy and precision. How do these two concepts relate to the idea of significant digits?
Soloha48 [4]

Answer:

Accuracy of a measured value refers to how close a measurement is to the correct value. The uncertainty in a measurement is an estimate of the amount by which the measurement result may differ from this value. Precision of measured values refers to how close the agreement is between repeated measurements.

Explanation:

3 0
3 years ago
Other questions:
  • A 0.999-g sample of a metal chloride, mcl2, is dissolved in water and treated with excess aqueous silver nitrate. The silver chl
    10·2 answers
  • Please answer as many as you can I need the help
    5·1 answer
  • _______ are organic compounds containing a C=O bond, having strong aromas, and known for being volatile. A. Carboxylic acids B.
    10·2 answers
  • What is the mass of a neutron?
    13·2 answers
  • Convert 8.7 mg to ibs
    13·2 answers
  • Which of the following is NOT true of electronegativity?
    14·1 answer
  • How to prepare 100 mL of lead nitrate Pb(NO3)2 ?
    10·1 answer
  • 1. please answer i really need your help
    9·2 answers
  • Select the correct empirical formula for each molecular formula given.
    12·1 answer
  • The standard gibbs free energy of formation of ________ is zero.
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!