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
Anni [7]
3 years ago
10

A 19.12 g mixture of Ca(NO3)2 and KCl is dissolved in 149 g of water. The freezing point of the solution was measured as −5.77 ∘

C . Calculate the mass percent of Ca(NO3)2 in the mixture. A list of ????f values can be found in th
Physics
1 answer:
hichkok12 [17]3 years ago
5 0

Answer:

The mass percentage of calcium nitrate is 31.23%.

Explanation:

Let the the mass of calcium nitrate be x and mass of potassium chloride be y.

Total mass of  mixture = 19.12 g

x + y = 19.12 g..(1)

Mass of solvent = 149 g = 0.149 kg

Freezing point of the solution,T_f = -5.77 °C

Molal freezing constant of water = 1.86 °C/m =1.86 °C/(mol/kg)

The van't Hoff factor contribution by calcium nitrate is 3 and by potassium chloride is 2.So:

i = 3

i' = 2

Freezing point of water = T = 0°C

\Delta T_f=T-T_f=0^oC-(-5.77^oC)=5.77^oC

\Delta T_f=i\times K_f\times m

Molality=m(mol/kg)=\frac{\text{Moles of solute}}{\text{mass of solvent in kg}}

5.77^oC=1.86 ^oC/(mol/kg)\times (\frac{ i\times x}{164 g/mol\times 0.149 kg}+\frac{i'\times y}{74.5 g/mol0.149 kg})

On solving we get:

\frac{3x}{164 g/mol}+\frac{2x}{74.5 g/mol}=0.4622 mol....(2)

Solving equation (1)(2) for x and y:

x =5.973 g

y = 13.147 g

Mass percent of Ca(NO_3)_2 in the mixture:

\frac{x}{19.21 g}\times 100=\frac{5.973 g}{19.12 g}=31.23\%

The mass percentage of calcium nitrate is 31.23%.

You might be interested in
This object is located 13.0 cm to the left of the lens and the image forms at 20.8 cm to the right of the lens.
Alina [70]

Answer:

0.125 cm

Explanation:

1/f = 1/d¡ + 1/d。

Find the focal point

(13.0^-1 + 20.8^-1) = 0.125 m

Focal point = 0.125 m  

6 0
2 years ago
Read 2 more answers
A heavy meterstick has a mass of 1 kg. When the meterstick is thrown like a spear past you, you measure its momentum to be 2mv.
CaHeK987 [17]

Answer:

Its length is measured to be 0.5 m

Explanation:

From theory of relativity (mass variation), we know that:

m = mo/√(1-v²/c²)

Where, m = relative mass

and, mo = rest mass

The momentum of stick while moving, will be:

P = mv

but, it is given in the form of rest mass as:

P = 2(mo)v

thus, by comparison;

2(mo)v = mv

using value of m from theory of relativity;

2(mo)v = (mo)v/√(1-v²/c²)

√(1-v²/c²) = 1/2     ______ eqn(1)

Now, for relativistic length (L), we have the formula from same theory of relativity;

L = (Lo)√(1-v²/c²)

The rest length (Lo) of meter stick is 1 m, and the remaining term on right side √(1-v²/c²), known as Lorentz Factor, can be given by eqn (1), as equal to 1/2.

Thus,

L = (1 m)(1/2)

<u>L = 0.5 m</u>

4 0
3 years ago
The temperature of a smelting furnace is found to be 2000 degree Celsius.find the temperature on Fahrenheit scale​
Dima020 [189]

Answer:

3632.

Explanation:

Based on the formula:

2000×(9/5)+32=3632

6 0
2 years ago
Olivia wants to find out whether a substance will fluoresce. She says she should put it in a microwave oven. Do you agree with h
andreyandreev [35.5K]
Disagree.
Fluoresce objects will only glow when put under actual Ultraviolet light. This is due to the molecules becoming excited by the ultraviolet radiation.


Microwaves give micro-waves that are present in another spectrum of wave length and will not be able to fluoresce the molecules. If it’s not “ultra violet “.... it’s not going to glow.
4 0
3 years ago
Read 2 more answers
If the mass of the sun is 1x, at least one planet will fall into the habitable zone if I place a planet in orbits___, ____, ____
nasty-shy [4]

If the mass of the sun is 1x, at least one planet will fall into the habitable zone. if I place a planet in orbits 2, 6, and 75, and all planets will orbit the sun successfully.

If the mass of the sun is 2x, at least one planet will fall into the habitable zone. if I place a planet in orbits 84, 1, and 5, and all planets will orbit the sun successfully.

If the mass of the sun is 3x, at least one planet will fall into the habitable zone if I place a planet in orbits 672, and 7 and all planets will orbit the sun successfully.

8 0
2 years ago
Other questions:
  • Calculate the refractive index of the substance if the speed of light in the medium is 210,000 km/s.
    12·1 answer
  • A car traveling at a constant speed travels 1000 feet in 12 seconds . In miles , how far will this car travel in 4 hours
    5·1 answer
  • Ahmed kept a balloon from his birthday for several days until it began to deflate and slowly sink to the ground. He wondered how
    8·2 answers
  • The greatest ocean depths on the earth are found in the marianas trench near the philippines. calculate the pressure due to the
    7·1 answer
  • Providing that it does not collide with another object, what is the most likely reason that an object moving through space would
    15·1 answer
  • How can you explain why there are so many hours of darkness on December 21? How can you explain why there are so many hours of d
    11·1 answer
  • What is true about coal as an energy source
    8·1 answer
  • True or false: a light source can emit more than one light ?
    7·1 answer
  • How will this substance ease the pain?​
    12·1 answer
  • If a quantity of heat equal to the magnitude of the change in mechanical energy of the water goes into the water, what is its in
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!