All categories

2 years ago

if the mole fractio of NaCl in an aqueous solution is 0.0927, what is the wt/wt% (percent by mass) of NaCl

Chemistry

1 answer:

Viktor [21]2 years ago

7 0

mole NaCl = 0.0927

mole H2O = 1.0000 - 0.0927 = 0.9073

then

mass NaCl = 0.0927mole x (0.9073g / mole) = 0.1022 g

mass H2O = 0.9073 mole x (18.02g / mole) = 16.35 g

and therefore;

mass % NaCl = [(0.1022g NaCl) / (58.45g NaCl + 18.016g H2O)] x 100% = 24.9%

=24.9%

You might be interested in

What wind direction change usually occurs as a cold front moves through an area?

Yanka [14]

Answer:

northern winds

Explanation:

8 0

3 years ago

Read 2 more answers

Consider an exceptionally weak acid, HA, with a Ka = 1x10 -20 . You make a 0.1M solution of the salt Na

Vedmedyk [2.9K]

Answer:

$pH=13$

Explanation:

Hello,

In this case, given the acid, we can suppose a simple dissociation as:

$HA\rightleftharpoons H^+ + A^-$

Which occurs in aqueous phase, therefore, the law of mass action is written by:

$Ka=\frac{[H^+][A^-]}{[HA]}$

That in terms of the change $x$ due to the reaction's extent we can write:

$1x10^{-20}=\frac{x*x}{0.1M-x}$

But we prefer to compute the Kb due to its exceptional weakness:

$Kb=\frac{Kw}{Ka}=\frac{1x10^{-14}}{1x10^{-20}} =1x10^{-6}$

Next, the acid dissociation in the presence of the base we have:

$Kb=\frac{[OH^-][HA]}{[A^-]}=1x10^{6}=\frac{x*x}{0.1-x}$

Whose solution is $x=0.0999M$ which equals the concentration of hydroxyl in the solution, thus we compute the pOH:

$pOH=-log([OH^-])=-log(0.0999)=1$

Finally, since the maximum scale is 14, we can compute the pH by knowing the pOH:

$pH+pOH=14\\\\pH=14-pOH=14-1\\\\pH=13$

Regards.

5 0

3 years ago

Read 2 more answers

As the amount of charge on two objects increases, the strength of the electrical force between the objects

Aleks [24]

Answer:

Increase is the answer

Explanation:

Increase is the answer hopes this helps you

6 0

2 years ago

Read 2 more answers

At 25 °c, what is the hydroxide ion concentration, [oh–], in an aqueous solution with a hydrogen ion concentration of [h ] = 3.0

chubhunter [2.5K]

As,

Water has a pkw=14

so it can be represented as,

[H+] [OH-] = 1*10^-14

If [H+] = 3*10^-5M

[OH-] = (1*10^-14) / ( 3*10^-5)

[OH-] = 3.3*10^-9 M

5 0

3 years ago

How does molecular attraction affect the amount of energy needed to create a phase change. Think about low, medium, and high

Art [367]

Answer:

When considering phase changes, the closer molecules are to one another, the stronger the intermolecular forces. Good! For any given substance, intermolecular forces will be greatest in the solid state and weakest in the gas state.

In the case of melting, added energy is used to break the bonds between the molecules. ... If heat is coming into a substance during a phase change, then this energy is used to break the bonds between the molecules of the substance. The example we will use here is ice melting into water.

5 0

2 years ago