All categories

3 years ago

Can you please answer the 5 attached questions?

Chemistry

1 answer:

Assoli18 [71]3 years ago

5 0

Answer:

10.4%

Explanation:

Recall that the formula for percent solution = mass of solute/mass of solution * 100

Mass of solute = 2.07 g

Mass of solution = 19.9 g

Hence mass percent of solute = 2.07/19.9 * 100

= 10.4%

You might be interested in

Look at the chemical equation below.

Alla [95]

8 Nitrogen, 4 oxygen, 2 N2O

8 0

3 years ago

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin pla

RSB [31]

Answer: The enthalpy change of the reaction is -27. kJ/mol

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 25.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{25.0mL}\\\\\text{Mass of water}=(1g/mL\times 25.0mL)=25g$

To calculate the heat released by the reaction, we use the equation:

$q=mc\Delta T$

where,

q = heat released

m = Total mass = [1.25 + 25] = 26.25 g

c = heat capacity of water = 4.18 J/g°C

$\Delta T$ = change in temperature = $T_2-T_1=(21.9-25.8)^oC=-3.9^oC$

Putting values in above equation, we get:

$q=26.25g\tiimes 4.18J/g^oC\times (-3.9^oC)=-427.9J=-0.428kJ$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of ammonium nitrate = 1.25 g

Molar mass of ammonium nitrate = 80 g/mol

Putting values in above equation, we get:

$\text{Moles of ammonium nitrate}=\frac{1.25g}{80g/mol}=0.0156mol$

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

q = amount of heat released = -0.428 kJ

n = number of moles = 0.0156 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction

Putting values in above equation, we get:

$\Delta H_{rxn}=\frac{-0.428kJ}{0.0156mol}=-27.44kJ/mol$

Hence, the enthalpy change of the reaction is -27. kJ/mol

4 0

4 years ago

A solution is made by adding 200 g table salt to 1

pochemuha

We say that the solution is unsaturated.

Explanation:

If the salt solubility is 36 g in 0.1 L of water then we can dissolve 360 g of salt in 1 L of water.

Because the solution contains 200 g of salt in 1 L of water, the solution is unsaturated because more salt can be added until we reach the saturation point.

We call the solution dilute when we compare the concentration of a solution with the concentration of another solution, but here we do not compare different solutions.

Learn more about:

solubility

brainly.com/question/9126711

#learnwithBrainly

7 0

4 years ago

Read 2 more answers

On day 5, only two turtles are on the beach. Describe an unknown variable that could have affected the data.

kompoz [17]

It's in beach bed .it was any various and Land reptile . it is production of eggs on the beach bed

4 0

4 years ago

Which of these relationships is true of an uncharged atom?

marusya05 [52]

Answer:

The correct option is C) The number of protons is equal to the number of electrons.

Explanation:

Atoms are made up of particles called protons, neutrons, and electrons. Protons and neutrons are in the center of the atom and form the nucleus, while electrons surround the nucleus. Electrons have a negative charge. The charge of the protons is positive and finally, the neutrons have no charge.

If the atom has no charge, this means that the total charge of the atomic nucleus, which is positive due to the presence of the protons, is equal to the negative charge of the electrons, so that it cancels out.

So, the correct option is C) The number of protons is equal to the number of electrons.

7 0

3 years ago