What type of energy is the sum of kinetic and potetinal energy in an object that is used to do work

A student dissolves of urea in of a solvent with a density of . The student notices that the volume of the solvent does not chan

Dimas [21]

The question incomplete , the complete question is:

A student dissolves of 18.0 g urea in 200.0 mL of a solvent with a density of 0.95 g/mL . The student notices that the volume of the solvent does not change when the urea dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to significant digits.

Answer:

The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.

Explanation:

Moles of urea = $\frac{18.0 g}{60 g/mol}=0.3 mol$

Volume of the solution = 200.0 mL = 0.2 L (1 mL = 0.001 L)

$Molarity(M)=\frac{\text{Moles of compound}}{\text{Volume of solution in L}}$

Molarity of the urea solution ;

$M=\frac{0.3 mol}{0.200 L}=1.50 M$

Mass of solvent = m

Volume of solvent = V = 200.0 mL

Density of the urea = d = 0.95 g/mL

$m=d\times V=0.95 g/mL\times 200.0 mL=190 g$

$m = 190 g = 190 \times 0.001 kg = 0.19 kg$

(1 g = 0.001 kg)

Molality of the urea solution ;

$Molality(m)=\frac{\text{Moles of compound}}{\text{Mass of solvent in kg}}$

$m=\frac{0.3 mol}{0.19 kg}=1.58 m$

The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.

7 0

2 years ago

Deposition can occur where wind or running water slows down? true or false

Shalnov [3]

Answer:

The answer is True.

Explanation:

6 0

2 years ago

Identify any solutes and solvents present in a mixture of 0.05 mol ethanol, 1 liter water, and 0.2 g hydrogen

Varvara68 [4.7K]

Answer:

Water is the solvent

Both the ethanol and the hydrogen peroxide are the solute

Explanation:

Both the hydrogen peroxide and ethanol are sisobable in water.

There are 0.05 moles of ethanol.

1 litreof water contains 55.55 moles of water.

0.2 g of hydrogen peroxide contains 0.2/34 = 0.0059 moles of hydrogen peroxide (the 34 is the molar mass of hydrogen peroxide).

Since there are more moles of water, water becomes the solvent and the other two liquids dissolve in it.

6 0

3 years ago

Polyester is a synthetic material used for many different purposes. It is produced from petroleum and natural gas. Producing pol

notka56 [123]

Answer:

A. Producing certain synthetic materials could have a greater environmental impact than disposing of them.

Explanation

I just did this question and got it right.

3 0

2 years ago

Acetic acid has a Kb of 2.93 °C/m and a normal boiling point of 118.1 °C. What would be the boiling point of a solution made by

alexdok [17]

Boiling point elevation is given as:

ΔTb=iKbm

Where,

ΔTb=elevation in the boiling point

that is given by expression:

ΔTb=Tb (solution) - Tb (pure solvent)

Here Tb (pure solvent)=118.1 °C

i for CaCO3= 2

Kb=2.93 °C/m

m=Molality of CaCO₃:

Molality of CaCO₃=Number of moles of CaCO₃/ Mass of solvent (Kg)

=(Given Mass of CaCO3/Molar mass of CaCO₃)/ Mass of solvent (Kg)

=(100.0÷100 g/mol)/0.4

= 2.5 m

So now putting value of m, i and Kb in the boiling point elevation equation we get:

ΔTb=iKbm

=2×2.93×2.5

=14.65 °C

boiling point of a solution can be calculated:

ΔTb=Tb (solution) - Tb (pure solvent)

14.65=Tb (solution)-118.1

Tb (solution)=118.1+14.65

=132.75

3 0

3 years ago