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1 year ago

A solution is prepared by mixing 200.0 g of water, H2O, and 300.0 g of

Chemistry

1 answer:

VikaD [51]1 year ago

7 0

Answer:

Mole Fraction (H₂O) = 0.6303

Mole Fraction (C₂H₅OH) = 0.3697

Explanation:

(Step 1)

Calculate the mole value of each substance using their molar masses.

Molar Mass (H₂O): 2(1.008 g/mol) + 15.998 g/mol

Molar Mass (H₂O): 18.014 g/mol

200.0 g H₂O 1 mole
--------------------- x ------------------ = 11.10 moles H₂O
18.014 g

Molar Mass (C₂H₅OH): 2(12.011 g/mol) + 6(1.008 g/mol) + 15.998 g/mol

Molar Mass (C₂H₅OH): 46.068 g/mol

300.0 g C₂H₅OH 1 mole
---------------------------- x -------------------- = 6.512 moles C₂H₅OH
46.068 g

(Step 2)

Using the mole fraction ratio, calculate the mole fraction of each substance.

moles solute
Mole Fraction = ------------------------------------------------
moles solute + moles solvent

11.10 moles H₂O
Mole Fraction = -------------------------------------------------------------
11.10 moles H₂O + 6.512 moles C₂H₅OH

Mole Fraction (H₂O) = 0.6303

6.512 moles C₂H₅OH
Mole Fraction = -------------------------------------------------------------
11.10 moles H₂O + 6.512 moles C₂H₅OH

Mole Fraction (C₂H₅OH) = 0.3697

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Given the following heats of combustion. CH3OH(l) + 3/2 O2(g) CO2(g) + 2 H2O(l) ΔH°rxn = -726.4 kJ C(graphite) + O2(g) CO2(g) ΔH

sergeinik [125]

Answer:

The standard enthalpy of formation of methanol is, -238.7 kJ/mole

Explanation:

The formation reaction of CH_3OH will be,

$C(s)+2H_2(g)+\frac{1}{2}O_2\rightarrow CH_3OH(g),\Delta H_{formation}=?$

The intermediate balanced chemical reaction will be,

$C(graphite)+O_2(g)\rightarrow CO_2(g), \Delta H_1=-393.5kJ/mole$ ..[1]

$H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(l), \Delta H_2=-285.8kJ/mole$ ..[2]

$CH_3OH(g)+\frac{3}{2}O_2(g)\rightarrow CO_2(g)+2H_2O(l) , \Delta H_3=-726.4kJ/mole$ ..[3]

Now we will reverse the reaction 3, multiply reaction 2 by 2 then adding all the equations, Using Hess's law:

We get :

$C(graphite)+O_2(g)\rightarrow CO_2(g) , \Delta H_1=-393.5kJ/mole$ ..[1]

$2H_2(g)+2O_2(g)\rightarrow 2H_2O(l) ,\Delta H_2=2\times (-285.8kJ/mole)=-571.6kJ/mol$ ..[2]

$CO_2(g)+2H_2O(l)\rightarrow CH_3OH(g)+\frac{3}{2}O_2(g) ,\Delta H_3=726.4kJ/mole$ [3]

The expression for enthalpy of formation of $C_2H_4$ will be,

$\Delta H_{formation}=\Delta H_1+2\times \Delta H_2+\Delta H_3$

$\Delta H=(-393.5kJ/mole)+(-571.6kJ/mole)+(726.4kJ/mole)$

$\Delta H=-238.7kJ/mole$

The standard enthalpy of formation of methanol is, -238.7 kJ/mole

4 0

3 years ago

Calculate the mass fraction of sodium chloride in the solution if 20 g of it is dissolved in 300 ml of water.

MA_775_DIABLO [31]

The mass fraction of sodium chloride is 0.0625

<h3>What is the mass fraction of sodium chloride in the solution?</h3>

The mass fraction of sodium chloride is the ratio of the mass of sodium chloride to the total mass of the solution.

The mass fraction of sodium chloride is determined as follows;

mass of sodium chloride = 20 g

mass of water = volume * density

density of water = 1 g/mL

volume of water = 300 mL

mass of water = 300 mL * 1 g/mL

mass of water = 300 g

total mass of solution = 20 + 300 = 320 g

mass fraction of sodium chloride = 20/320

mass fraction of sodium chloride = 0.0625

Learn more about mass fraction at: brainly.com/question/14783710

#SPJ1

5 0

1 year ago

I need help with this anyone?

valkas [14]

Just look it up on goog^le or a chart

5 0

3 years ago

Use your calculator to determine the answer to the following calculation:<br> 1.0×10^−15/4.2×10^−7

lianna [129]

1.0×10^−15/4.2×10^−7=<span>2.3809524e-23 Hoped I helped!</span>

8 0

3 years ago

Question 9

Evgesh-ka [11]

Answer:

0.382 atm

Explanation:

In order to find the pressure, you need to know the moles of carbon dioxide (CO₂) gas. This can be found by multiplying the mass (g) by the molar mass (g/mol) of CO₂. It is important to arrange the conversion in a way that allows for the cancellation of units.

Molar Mass (CO₂): 12.011 g/mol + 2(15.998 g/mol)

Molar Mass (CO₂): 44.007 g/mol

15 grams CO₂ 1 mole
---------------------- x ------------------------ = 0.341 moles CO₂
44.007 grams

To find the pressure, you need to use the Ideal Gas Law equation.

PV = nRT

In this equation,

-----> P = pressure (atm)

-----> V = volume (L)

-----> n = moles

-----> R = Ideal Gas Constant (0.08206 atm*L/mol*K)

-----> T = temperature (K)

After you convert Celsius to Kelvin, you can plug the given and calculated values into the equation and simplify to find the pressure.

P = ? atm R = 0.08206 atm*L/mol*K

V = 20 L T = 0 °C + 273.15 = 273.15 K

n = 0.341 moles

PV = nRT

P(20 L) = (0.341 moles)(0.08206 atm*L/mol*K)(273.15 K)

P(20 L) = 7.64016

P = 0.382 atm

7 0

2 years ago