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
Yuliya22 [10]
3 years ago
6

A certain substance X has a normal boiling point of 134.5°C and a molal boiling point elevation constant =Kb1.36·°C·kgmol−1 . Ca

lculate the boiling point of a solution made of 76.g of urea NH22CO dissolved in 850.g of X . Be sure your answer has the correct number of significant digits.
Chemistry
1 answer:
erastova [34]3 years ago
3 0

Answer:

136.5°C

Explanation:

Given data

  • Boiling point of X: 134.5°C
  • Molal boiling point elevation constant (Kb): 1.36·°C·kg.mol⁻¹

We can calculate the elevation in the boiling point (ΔT) using the following expression.

ΔT = Kb × m

where,

m is the molality

The molar mass of urea is 60.06 g/mol. The moles of urea corresponding to 76 g is:

76 g × (1 mol/60.06g) = 1.3 mol

The mass of the solvent (X) is 850 g = 0.850 kg.

The molality is:

m = 1.3 mol / 0.850 kg = 1.5 mol/kg

Then,

ΔT = Kb × m

ΔT = 1.36·°C·kg.mol⁻¹ × 1.5 mol/kg

ΔT = 2.0 °C

The boiling point of the solution is

134.5°C + 2.0°C = 136.5°C

You might be interested in
"Compounds A and B react to give a single product, C. Write the rate law for each of the following cases and determine the units
olasank [31]

Answer:

Part a: <em>Units of k is </em>M^{-2}s^{-1}<em> where reaction is first order in A and second order in B</em>

Part b: <em>Units of k is </em>M^{-1}s^{-1}<em> where reaction is first order in A and second order overall.</em>

Part c: <em>Units of k is </em>M^{-1}s^{-1}<em> where reaction is independent of the concentration of A and second order overall.</em>

Part d: <em>Units of k is </em>M^{-3}s^{-1}<em> where reaction reaction is second order in both A and B.</em>

Explanation:

As the reaction is given as

A+B \rightarrow C

where as the rate is given as

r=k[A]^x[B]^y

where x is the order wrt A and y is the order wrt B.

Part a:

x=1 and y=2 now the reaction rate equation is given as

r=k[A]^1[B]^2

Now the units are given as

r=k[A]^1[B]^2\\M/s =k[M]^1[M]^2\\M/s =k[M]^{1+2}\\M/s =k[M]^{3}\\M^{1-3}/s =k\\M^{-2}s^{-1} =k

The units of k is M^{-2}s^{-1}

Part b:

x=1 and o=2

x+y=o

1+y=2

y=2-1

y=1

Now the reaction rate equation is given as

r=k[A]^1[B]^1

Now the units are given as

r=k[A]^1[B]^1\\M/s =k[M]^1[M]^1\\M/s =k[M]^{1+1}\\M/s =k[M]^{2}\\M^{1-2}/s =k\\M^{-1}s^{-1} =k

The units of k is M^{-1}s^{-1}

Part c:

x=0 and o=2

x+y=o

0+y=2

y=2

y=2

Now the reaction rate equation is given as

r=k[A]^0[B]^2

Now the units are given as

r=k[B]^2\\M/s =k[M]^2\\M/s =k[M]^{2}\\M^{1-2}/s =k\\M^{-1}s^{-1} =k

The units of k is M^{-1}s^{-1}

Part d:

x=2 and y=2

Now the reaction rate equation is given as

r=k[A]^2[B]^2

Now the units are given as

r=k[A]^2[B]^2\\M/s =k[M]^2[M]^2\\M/s =k[M]^{2+2}\\M/s =k[M]^{4}\\M^{1-4}/s =k\\M^{-3}s^{-1} =k

The units of k is M^{-3}s^{-1}

7 0
3 years ago
Why sodium chloride is a poor conductor of electricity in solid state?​
aev [14]

Answer:

Because the electrons in this ionic compound arent free to move and so cannot carry charge. For an iconic compound to conduct electricity it must be a liquid, either in a molten form or dissolved in water.

Explanation:

Is this clear?

5 0
2 years ago
2. What is one effect of convection currents in the mantle?
Rom4ik [11]

Answer:

D no. is the answer of your question

8 0
3 years ago
At STP, solid carbon can exist as graphite or as diamond. These two forms of carbon have(1) the same properties and the same cry
Umnica [9.8K]
Answer=4

Diamonds and graphite have different properties and different crystal structures.

In diamonds, the carbon atoms are arranged tetrahedrally, whereas carbon atoms are arranged in an infinite array in graphite. Graphite has a lower density than diamonds... Diamonds are the best conductor of heat that we know of... the properties differ greatly 
3 0
2 years ago
During the fall season in North America daylight gradually?
Gala2k [10]

b, the sunlight decreases because the sun is tilted on an axis and towards the fall and winter times, it gets shorter

5 0
3 years ago
Other questions:
  • A fossilized leaf contains 24% of its normal amount of carbon 14. how old is the fossil (to the nearest year)? use 5600 years as
    10·1 answer
  • Silver sulfadiazine burn-treating cream creates a barrier against bacterial invasion and releases antimicrobial agents directly
    9·1 answer
  • A chemistry student needs 50.0 g of methyl acetate for an experiment. By consulting the CRC Handbook of Chemistry and Physics, t
    11·1 answer
  • Which of the following occurs when a covalent bond forms? Which of the following occurs when a covalent bond forms? Partial char
    15·1 answer
  • The nucleus of an atom ok K-42 contains
    7·1 answer
  • Imagine that you started from 5.00 grams of BaCl2.2H2O, which is your limiting reactant. If only 70% of BaCl2.2H2O gives the des
    8·1 answer
  • How can naphthalene be separated from a mixture of kbr and sand?
    8·2 answers
  • 3HCl(aq) + Al(OH)3(aq) = AIC13(aq) + 3H2O(1)
    7·1 answer
  • Study the scenario. The particles in a system are moving around very slowly. A few minutes later, the particles are moving, on a
    7·1 answer
  • 3. Describe short-term factors that could influence yearly data within this system
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!