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3 years ago

How many moles and molecules are there in 250g of hydrogen nitrate, HNO3

Chemistry

1 answer:

Viefleur [7K]3 years ago

6 0

Answer:

Number of molecules = 23.9 × 10²³ molecules

Number of moles = 3.97 mol

Explanation:

Mass of HNO₃ = 250 g

Number of moles = ?

Number of molecules = ?

Solution:

Number of moles = mass / molar mass

Number of moles = 250 g/63 g/mol

Number of moles = 3.97 mol

Number of molecules:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 250 g of HNO₃:

250 g/ 63 g/mol = 3.97 mole

3.97 × 6.022 × 10²³ molecules = 23.9 × 10²³ molecules

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3 years ago

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3 years ago

What is the vapor pressure of the solution if 35.0 g of water is dissolved in 100.0 g of ethyl alcohol at 25 ∘C? The vapor press

masya89 [10]

Answer: The vapor pressure of the solution is 43.55 mmHg

Explanation:

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

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For water:

Given mass of water = 35.0 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{35.0g}{18g/mol}=1.944mol$

For ethyl alcohol:

Given mass of ethyl alcohol = 100.0 g

Molar mass of ethyl alcohol = 46 g/mol

Putting values in equation 1, we get:

$\text{Moles of ethyl alcohol}=\frac{100.0g}{46g/mol}=2.174mol$

Total moles of solution = [1.944 = 2.174] moles = 4.118 moles

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

For water:

$\chi_{\text{water}}=\frac{n_{\text{water}}}{n_{\text{water}}+n_{\text{ethyl alcohol}}}$

$\chi_{water}=\frac{1.944}{4.118}=0.472$

For ethyl alcohol:

$\chi_{\text{ethyl alcohol}}=\frac{n_{\text{ethyl alcohol}}}{n_{\text{water}}+n_{\text{ethyl alcohol}}}$

$\chi_{\text{ethyl alcohol}}=\frac{2.174}{4.118}=0.528$

Dalton's law of partial pressure states that the total pressure of the system is equal to the sum of partial pressure of each component present in it.

To calculate the vapor pressure of the solution, we use the law given by Dalton, which is:

$P_T=\sum_{i=1}^n (p_i\times \chi_i)$

Or,

$P_T=[(p_{\text{water}}\times \chi_{\text{water}})+(p_{\text{ethyl alcohol}}\times \chi_{\text{ethyl alcohol}}$

We are given:

Vapor pressure of water = 23.8 mmHg

Vapor pressure of ethyl alcohol = 61.2 mmHg

Putting values in above equation, we get:

$p_T=[(23.8\times 0.472)+(61.2\times 0.528)]\\\\p_T=43.55mmHg$

Hence, the vapor pressure of the solution is 43.55 mmHg

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3 years ago

Which is true about the pH values of a 1.0 M solution of HCl (a strong acid) and a 1.0 M solution of HC2H3O2 (a weak acid)?

Neko [114]

Answer:

C. pH values are different because the $HC_2H_3O_2$ solution partially ionizes and the HCl solution ionizes 100 percent.

Explanation:

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Thus, strong acids furnish greater concentration of protons as compared to weak acid when same concentration of both types are taken.

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3 years ago

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Answer:

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Explanation:

Your welcome

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3 years ago