Each of the colors of light in the visible light spectrum has...

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 ∘

hichkok12 [17]

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%.

5 0

3 years ago

An engine converts 95% of its energy to mechanical. What happens to the other 5% of its energy?

Elza [17]

Answer:

Here, 5% of energy wasted as a heat lost or work done against frictional forces.

Explanation:

No engine has yet made that can convert its all input energy into mechanical energy. Some of the input energy goes in vain in the form of heat and friction.

6 0

3 years ago

An air-track glider undergoes a perfectly inelastic collision with an identical glider that is initially at rest. what fraction

Allisa [31]

In this collision, 1/2 of the initial kinetic energy of the first glider is converted into thermal energy.

<h3>In plain English, what is kinetic energy?</h3>

An object's strength as a result ofstrength an object has as a result or motion is known as kinetic energy. Toorder to accelerate an object, a force must be applied. Applying force requires effort on our part. When the work is done, power is transported to the thing, which causes it to move at the athe new, constant pace.

<h3>What does kinetic energy mean, or what are some instances?</h3>

The motion energy is known as kinetic energy, and it is manifested when a particle, object, or group if particles moves. Any moving object uses kinetic energy, including people walking, baseballs being thrown, food falling from tables, and charged particles in electric fields.

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8 0

1 year ago

A drag racer starts from rest and accelerates at 10 m/s squared for the

nika2105 [10]

Answer:

54 $\frac{m}{s}$