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3 years ago

A liquid is placed in an evacuated, sealed flask. When will this closed system reach dynamic equilibrium?

Chemistry

2 answers:

Valentin [98]3 years ago

7 0

When the rate of evaporation equals the rate of condensation

timurjin [86]3 years ago

4 0

The liquid will stop converting into vapor. This process is to balanced the amount of substance of both phases inside the flask.

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Stearic acid (C18H36O2) is a fatty acid, a molecule with a long hydrocarbon chain and an organic acid group (COOH) at the end. I

Paha777 [63]

Answer:

There is 9671 Kj of heat released

Explanation:

Step 1: The balanced equation:

C18H36O2(s) + 26O2(g) --> 18CO2(g)+18H2O(g)

This means for 1 mole of C18H36O2 consumed there is 26 moles of O2 needed to produce 18 moles of CO2 and 18 moles of H2O.

Step 2: Calculate the heat of combustion

ΔH (combustion) = [18*(ΔHf of CO2) + 18*(ΔHf of H2O)] - [1*(ΔHf of C18H36O2) + 26*(ΔHf of O2)]

ΔH (combustion) = [18*(-394 kJ/mol) + 18*(-242 kJ/mol)] - [1*(-948 kJ/mol) + 26*(0 kJ/mol)]

ΔH (combustion) = [(-7092 kJ/mol) + (-4356 kJ/mol)] - (-948 kJ/mol)

= -10500 kJ/mol

ΔH (combustion) = heat released / number of moles of stearic acid

Step 3: Calculate moles of stearic acid

moles of stearic acid = mass / Molar mass of stearic acid

moles of stearic acid = 262g / 284.48 g/mole = 0.921 moles

Step 4: Calculate moles of oxygen

moles of O2 = 914.5 / 32g/mole

moles of O2 = 28.578125 moles

Stearic acid is the limiting reactant: it will completely react

There will react 26*0.921 mole = 23.946 mole of O2

This means there will remain 4.63 moles of O2

Step 5: Calculate heat released

q = (ΔH combustion) * (moles of stearic acid) = (-10500 kJ/mol) * (0.921 moles) = 9671 Kj

There is 9671 Kj of heat released

6 0

3 years ago

When 3.0 grams of H2 is reacted with excess C at constant pressure, the reaction forms CH4 and releases 53.3 kJ of heat. C(s) +

Murrr4er [49]

Answer:

THE ENTHALPY OF REACTION IN KJ/MOL OF CH4 IS 7.07 KJ/MOL.

Explanation:

Mass of H2 = 3 g

Molar mass of H2 = 2 g/mol

Heat released = 53.3 kJ

Equation of the reaction:

C(s) + 2H2(g) -------> CH4(g)

First:

Calculate the number of moles of H2 that was used:

Number of moles = mass / molar mass

Number of moles = 3g / 2g

Number of moles = 1.5 moles

So therefore, when 53.3 kJ of heat was released from the reaction, 1.5 moles of hydrogen was used.

From the equation of the reaction, one mole of carbon reacts with two moles of hydrogen to form one mole of methane.

For 3 g of hydrogen, 1.5 mole of hydrogen is involved.

It means:

1.5 moles of hydrogen reacts with 0.75 moles of carbon and produces 0.75 moles of methane. This is so because the reaction occurs in 1: 2: 1 in respect to carbon, hydrogen and methane respectively.

So we can say that the production of 0.75 mole of methane will evolve 53.3 kJ of heat.

0.75 mole of methane releases 53.3 kJ of heat.

1 mole of methane will release ( 53.3 kJ * 1 / 0.75 )

= 71.0666 kJ of heat

In conclusion, the enthalpy of the reaction in kJ/ mole of CH4 is 71.07 kJ/mol.

7 0

3 years ago

The electronic configuration of an element is given below.

drek231 [11]

Answer:

C. It is reactive because it must gain two electrons to have a full outermost energy level.

Step-by-step explanation:

The electron configuration of this element ends in 2s²2p⁴.

A filled energy level would end in 2s²2p⁶.

The element will be reactive, because it must gain electrons to have a full energy level, and it needs two more electrons to do this.

4 0

3 years ago

Which change in the sun’s gravity would occur if the sun’s mass were reduced by one-half?(1 point)

Kisachek [45]

Answer:

Gravity or the gravitational force is defined as the force of attraction occurring between all states of matter. The sun’s gravity, mass, and radius plays a crucial role in the properties of the Sun.

Explanation:

The gravity of an object can be determined using the formula:

$\text{g}&=\frac{\text{GM}}{\text{R}^{2} }}$

Now, according to the question, the mass of the sun is halved, which will be written as:

$\text{g}&=\frac{\text{G}\frac{\text{M}}{2}}{\text{R}^{2} }}$

Thus, according to the equation, the mass of an object is directly proportional to the gravitational field. since, the mass of the Sun is reduced to half, the gravity of the Sun will be halved.

8 0

3 years ago

Read 2 more answers

How much heat (in Joules) is needed to raise the temperature of 257g of ethanol (cethanol=2.4 J/g°C) by 49.1°C?

Sonbull [250]

Answer:

Q = 30284.88 j

Explanation:

Given data:

Mass of ethanol = 257 g

Cp = 2.4 j/g.°C

Chnage in temperature = ΔT = 49.1°C

Heat required = ?

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Now we will put the values in formula.

Q = 257 g× 2.4 j/g.°C × 49.1 °C

Q = 30284.88 j

8 0

3 years ago