Ask question

Ask question

All categories

3 years ago

7

How much energy in kilojoules is released when 23.4 g of ethanol vapor at 83.0 ∘C is cooled to -15.0 ∘C ?

1 answer:

slamgirl [31]3 years ago

5 0

Answer : The amount of in kilojoules released is, -5.53 kJ

Explanation :

Formula used :

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat released = ?

c = specific heat of ethanol = $2.41J/g^oC$

m = mass of ethanol = 23.4 g

$T_{final}$ = final temperature = $-15.0^oC$

$T_{initial}$ = initial temperature = $83.0^oC$

Now put all the given values in the above formula, we get:

$q=23.4g\times 2.41J/g^oC\times (-15.0-83.0)^oC$

$q=-5526.612J=-5.53\times 10^3J=-5.53kJ$

Therefore, the amount of in kilojoules released is, -5.53 kJ

You might be interested in

Intermolecular forces do not have any effect on determining the physical properties of

djyliett [7]

Answer:

False

Explanation:

The physical properties of melting point, boiling point, vapor pressure, evaporation, viscosity, surface tension, and solubility are related to the strength of attractive forces between molecules. These attractive forces are called Intermolecular Forces.

6 0

3 years ago

The reaction of hydrogen(g) with fluorine(g) to form hydrogen fluoride(g) proceeds as follows: H2(g) + F2(g) 2 HF(g) When 0.647

Nata [24]

<u>Answer:</u> The value of $\Delta H$ for the reaction will be -537 kJ

<u>Explanation:</u>

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

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of hydrogen gas = 0.647 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

$\text{Moles of hydrogen gas}=\frac{0.647g}{2g/mol}=0.324mol$

We are given:

Energy released for 0.324 moles of hydrogen reacted is 174 kJ

For the given chemical reaction:

$H_2(g)+F_2(g)\rightarrow 2HF(g)$

By Stoichiometry of the reaction:

When 0.324 moles of hydrogen gas is reacted, the energy evolved is 174 kJ

So, when 1 mole of hydrogen gas will react, the energy evolved will be = $\frac{174kJ}{0.324mol}\times 1mol=537kJ$

<u>Sign convention of heat:</u>

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

Hence, the value of $\Delta H$ for the reaction will be -537 kJ

6 0

3 years ago

When shopping for major appliances, people should look for high energy-rating numbers because those items _____.

madam [21]

The answer would be :Use less energy

6 0

3 years ago

Read 2 more answers

The molecular weight of table salt, NaCl, is 58.5 g/mol. A tablespoon of salt weighs 6.37 grams. Calculate the number of moles o

LiRa [457]

There are 0.109 moles of NaCl in one tablespoon of salt. This is found by dividing the number of grams you have by the molecular weight.

3 0

3 years ago

Read 2 more answers

Consider the reaction: Mg(OH)₂ (s) ⇌ Mg²⁺ (aq) + 2 OH⁻ (aq)

balandron [24]

The value of Kc for the equilibrium is 0.150 mole² / litre ²

<u>Explanation:</u>

<u>Given:</u>

An equilibrium mixture in an 1.00 L vessel contains 5.30 moles of

Mg(OH )₂ 0.800 moles of Mg²⁺ and 0.0010 moles OH₋

We have to find the value of Kc

Step 1: Find the equilibrium Concentration.
Step 2: Substitute the values in the equation.
Step 3: Find the value of Kc.
I have attached the document for the detailed explanation

The value of Kc for the equilibrium is 0.150 mole² / litre ²

8 0

3 years ago