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4 years ago

How many grams of a 23.4% by mass naf solution is needed if you want to have 1.33 moles of naf?

1 answer:

6 0

Percentage by mass is the mass of NaF present in 100 g of the solution.
the percentage by mass of NaF is 23.4 %
this means that in 100 g of solution, mass of NaF present is 23.4 g
the number of moles of NaF present - 1.33 mol
mass of NaF - 1.33 mol x 42 g/mol = 55.9 g
when there's 23.4 g of NaF - mass of solution is 100 g
therefore when there's 55.9 g of NaF - mass of solution is 100 / 23.4 x 55.9
= 239 g
mass of solution required is 239 g

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An equilibrium mixture of PCl5(g), PCl3(g), and Cl2(g) has partial pressures of 217.0 Torr, 13.2 Torr, and 13.2 Torr, respective

katovenus [111]

Answer:

The new partial pressures after equilibrium is reestablished:

$PCl_3,p_1'=6.798 Torr$

$Cl_2,p_2'=26.398 Torr$

$PCl_5,p_3'=223.402 Torr$

Explanation:

$PCl_3(g) + Cl_2(g)\rightleftharpoons PCl_5(g)$

At equilibrium before adding chlorine gas:

Partial pressure of the $PCl_3=p_1=13.2 Torr$

Partial pressure of the $Cl_2=p_2=13.2 Torr$

Partial pressure of the $PCl_5=p_3=217.0 Torr$

The expression of an equilibrium constant is given by :

$K_p=\frac{p_1}{p_1\times p_2}$

$=\frac{217.0 Torr}{13.2 Torr\times 13.2 Torr}=1.245$

At equilibrium after adding chlorine gas:

Partial pressure of the $PCl_3=p_1'=13.2 Torr$

Partial pressure of the $Cl_2=p_2'=?$

Partial pressure of the $PCl_5=p_3'=217.0 Torr$

Total pressure of the system = P = 263.0 Torr

$P=p_1'+p_2'+p_3'$

$263.0Torr=13.2 Torr+p_2'+217.0 Torr$

$p_2'=32.8 Torr$

$PCl_3(g) + Cl_2(g)\rightleftharpoons PCl_5(g)$

At initail

(13.2) Torr (32.8) Torr (13.2) Torr

At equilbriumm

(13.2-x) Torr (32.8-x) Torr (217.0+x) Torr

$K_p=\frac{p_3'}{p_1'\times p_2'}$

$1.245=\frac{(217.0+x)}{(13.2-x)(32.8-x)}$

Solving for x;

x = 6.402 Torr

The new partial pressures after equilibrium is reestablished:

$p_1'=(13.2-x) Torr=(13.2-6.402) Torr=6.798 Torr$

$p_2'=(32.8-x) Torr=(32.8-6.402) Torr=26.398 Torr$

$p_3'=(217.0+x) Torr=(217+6.402) Torr=223.402 Torr$

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3 years ago

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Answer:

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4 years ago

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Determine whether each statement describes an electromagnetic wave, a mechanical wave, or both types of wave.

KiRa [710]

The question is incomplete, the complete question is;

Which statement describes a difference between electromagnetic and mechanical waves?

A. Mechanical waves cannot be longitudinal, but electromagnetic waves can.

B. Electromagnetic waves cannot move particles, but mechanical waves can.

C. Electromagnetic waves do not require a medium, but mechanical waves do.

D. Mechanical waves do not transfer energy, but electromagnetic waves do.

Answer:

Electromagnetic waves do not require a medium, but mechanical waves do.

Explanation:

A wave is defined as a disturbance along a medium which transfers energy. Waves may be classified as mechanical waves or electromagnetic waves based on their medium of propagation.

A mechanical wave requires a material medium for propagation. An example of a mechanical wave is sound waves. Sound waves are propagated in air.

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