Please help with 20-23 ( you can write short sentences)

A student dissolves of 15 g aniline in of a solvent with a density of . The student notices that the volume of the solvent does

VikaD [51]

The given question is incomplete. The complete question is ;

A student dissolves of 15 g aniline in 200 ml of a solvent with a density of 1.05 g/ml. The student notices that the volume of the solvent does not change when the aniline dissolves in it. Calculate the molarity and molality of the student's solution. Be sure each of your answer entries has the correct number of significant digits.

Answer: The molarity is 0.81 M and molality is 0.82 m

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute

$V_s$ = volume of solution in ml = 200 ml

${\text {moles of solute}=\frac{\text {given mass}}{\text {molar mass}}=\frac{15g}{93g/mol}=0.16mol$

Now put all the given values in the formula of molarity, we get

$Molarity=\frac{0.16\times 1000}{200}=0.81M$

Thus molarity is 0.81 M

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

$Molarity=\frac{n\times 1000}{W_s}$

where,

n = moles of solute

$W_s$ = weight of solvent in g

${\text {moles of solute}=\frac{\text {given mass}}{\text {molar mass}}=\frac{15g}{93g/mol}=0.16mol$

Mass of solution = $Density\times Volume=1.05g/ml\times 200ml=210g$

mass of solvent = mass of solution - mass of solute = (210 - 15) g = 195 g

Now put all the given values in the formula of molality, we get

$Molality=\frac{0.16\times 1000}{195g}=0.82mole/kg$

Therefore, the molality of solution is 0.82m

3 0

3 years ago

14. What are the two<br>main branches of science?

Vlada [557]

Answer:

Physical science

Life science

Explanation:

3 0

3 years ago

I need Helpppp with my chemistry while we are out of school. I don't have a good teacher and he's not helping since it's his las

9966 [12]

Answer:

im not sure but I hope this helps

Explanation:

I believe the equivalents is just the moles reactant/moles limiting reactant

water has a denisty of 1 g/mL. 1 L is 1000 ml so there are 1000g/L.

the molar mass of water is 18g/mol if you use the Liters in the equation above you can find the number of grams present. divide this number you found by 18 to find the moles.

now take the amount of the other reactant given and divide it by its own molar mass. this will give you the number of moles of that reactant.

divide the moles of water by the moles of the reactant and that is the equivalent.

to find the normality you take this number and divide it by the number of liters.

5 0

3 years ago

1. Explain the arrangements of electrons in the atom and include what valence electrons are.

mrs_skeptik [129]

Answer: Electrons are organized into shells and subshells around nuclei. The electron configuration states the arrangement of electrons in shells and subshells. Valence electrons are in the highest numbered shell.

7 0

4 years ago

If 4.00 moles of a gas at a pressure of 5.40 atm have a volume of 129 L, what is the temperature?

Alexus [3.1K]

Answer:

2121 K

Explanation:

With the numbers given in the problem, this is the math.

7 0

3 years ago