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3 years ago

Which change absorbs heat?

Chemistry

2 answers:

Sphinxa [80]3 years ago

4 0

Answer:

Using a Laptop computer

viktelen [127]3 years ago

4 0

Answer:

Frying an egg I do believe becuase it has to absorb the heat in order to cook.

Explanation:

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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

4 0

3 years ago

What type of mixture is separated by effusion and condensation?

icang [17]

Answer:

c is the answer then check it out

6 0

3 years ago

Which of the following BEST states the Law of Conservation of Matter? *

Nookie1986 [14]

Answer:

A. The total mass of the reactants in a reaction equals the total mass of the product(s).

Explanation:

The law of conversation of matter tells us that in a chemical reaction, matter is never created or destroyed, it's simply converted from one form to another. So the mass of reactants should always equal the mass of the products in a chemical reaction.

6 0

2 years ago

A sample of gas has an initial volume of 3.62 L at a pressure of 0.987 atm. If the volume of the gas decreases to 2.50 L, what w

statuscvo [17]

Answer:

0.033 atm

Explanation:

PV=nRT

rule of 1 for T and n

P= nRT/V

P= 1(.08206)1)/ 2.50

0.033 atm = pressure

3 0

3 years ago

Which of the following questions is outside the scope of science?

Airida [17]

A. How religion and philosophy different
All the other choices (b-d) can be explained by science while a can be explain by history I think

4 0

3 years ago