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2 years ago

According to the big bang theory, which statement is accurate about how the universe came to be?

Chemistry

1 answer:

Lady bird [3.3K]2 years ago

8 0

Answer:

Stars and Galaxies formed

Explanation:

I'm pretty sure that this is the answer

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Toluene (C6H5CH3 ), an organic compound often used as a solvent in paints, is mixed with a similar organic compound, benzene (C6

Sergeeva-Olga [200]

Explanation:

The given data is as follows.

Weight of solute = 75.8 g, Molecular weight of solute (toulene) = 92.13 g/mol, volume = 200 ml

Therefore, molarity of toulene is calculated as follows.

Molarity = $\frac{\text{weight of solute}}{\text{molecular weight of solute}} \times \frac{1000}{\text{volume of solution in ml}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{200 ml}$

= 4.11 M

Hence, molarity of toulene is 4.11 M.

As molality is the number of moles of solute present in kg of solvent.

So, we will calculate the molality of toulene as follows.

Molality = $\frac{\text{given weight of solute}}{\text{given molecular weight of solute}} \times \frac{1000}{\text{weight of solvent in grams}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{95.6 g}$

= 8.6 m

Hence, molality of given toulene solution is 8.6 m.

Now, calculate the number of moles of toulene as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{75.8 g}{92.13 g/mol}$

= 0.8227 mol

Now, no. of moles of benzene will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{95.6 g}{78.11 g/mol}$

= 1.2239 mol

Hence, the mole fraction of toulene is as follows.

Mole fraction = $\frac{\text{moles of toulene}}{\text{total moles}}$

= $\frac{0.8227 mol}{(0.8227 + 1.2239) mol}$

= 0.402

Hence, mole fraction of toulene is 0.402.

As density of given solution is 0.857 $g/cm^{3}$ so, we will calculate the mass of solution as follows.

Density = $\frac{mass}{volume}$

0.857 $g/cm^{3}$ = $\frac{mass}{200 ml}$ (As 1 $cm^{3}$ = 1 g)

mass = 171.4 g

Therefore, calculate the mass percent of toulene as follows.

Mass % = $\frac{\text{mass of solute}}{\text{mass of solution}} \times 100$

= $\frac{75.8 g}{171.4 g} \times 100$

= 44.22%

Therefore, mass percent of toulene is 44.22%.

8 0

4 years ago

It has been proven that North America is moving west about 2 cm per year. How many kilometers wouldn’t move in 5000 years

Viefleur [7K]

0.1 km

2cm/year * 5000 yrs = 10000 cm

1cm= .01 m

1km = 1000 m

so the answer is 0.1 km

7 0

3 years ago

How many electrons are shared in the Lewis structure

Diano4ka-milaya [45]

Hey there,

Answer:

4 valence electrons.

Hope this helps :D

<em>~Top☺</em>

3 0

3 years ago

Need help on this question asap pleasee I would really appreciate it

Elza [17]

Answer:

See Explanation

Explanation:

An endothermic reaction is one in which energy is absorbed and the change in enthalpy for the reaction is positive.

If we look at the reaction 2HgO + 45kcal ----> 2Hg + O2; we will notice that

i) 45kcal of energy was taken in (absorbed) for the reaction to occur

ii) The value of the reaction enthalpy is positive

For these two reasons, the reaction is an endothermic reaction as written.

6 0

3 years ago

Someone help me pleasee?

Kamila [148]

Maybe its the second one

7 0

3 years ago