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2 years ago

Enthalpy change depends on the rate at which a substance is heated or cooled true or false

1 answer:

6 0

Enthalpy is a thermodynamic quantity that describes the heat content of a system, that can not be measured directly. That's why we measure change in enthaply, measured in the units joules. The statement that e<span>nthalpy change depends on the rate at which a substance is heated or cooled is false. Enthalpy change depends only on the following factors:
-</span><span>physical state of reactants and products
- quantity of reactants</span><span>
- allotropic modifications
- temperature and pressure</span><span>
</span>

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If we react 5.4g of sodium chloride with an unknown amount of fluorine gas, we produce 4.9g of sodium fluoride and 3.7g chlorine

Bumek [7]

Answer:

4.43 g

Explanation:

The reaction between sodium chloride and flourine gas is given as;

NaCl + F2 --> NaF + Cl2

From the stochiometry of the equation;

1 mol of NaCl reacts eith 1 mol of F2 to form 1 mol of NaF and Cl2

Mass of 1 mol of F2 = 38g

Mass of 1 mol of sodium flouride, NaF = 42g

This means 38g of flourine reacted with NaCl to form 42g of NaF

xg of F2 would form 4.9g of NaF

38 = 42

x = 4.9

x = 4.9 * 38 / 42

x = 4.43 g

4 0

2 years ago

The average rate of disappearance of ozone in the reaction 2o3(g) → 3o2(g) is found to be 7.25×10–3 atm over a certain interval

worty [1.4K]

<h3><u>Answer</u>;</h3>

1.0875 x 10-2 atm

<h3><u>Explanation;</u></h3>

2O3(g) → 3O2(g)

rate = -(1/2)∆[O3]/∆t = +(1/3)∆[O2)/∆t

The average rate of disappearance of ozone ... is found to

be 7.25 × 10–3 atm over a certain interval of time.

This means (ignoring time)

∆[O3]/∆t = -7.25 × 10^–3 atm

(it is disappearing, thus the negative sign)

rate = -(1/2)∆[O3]/∆t

rate = -(1/2)*(-7.25 × 10^–3 atm)

= 3.625 × 10^–3 atm

Now use the other part of the expression:

rate = +(1/3)∆[O2)∆t

3.625 × 10–3 atm = +(1/3)∆[O2)/t

∆[O2)/∆t = (3)*(3.625× 10^–3 atm)

= 1.0875 x 10-2 atm over the same time interval

4 0

3 years ago

Which of the following best describes the solar radiation absorbed by and radiated from earth?

FinnZ [79.3K]

Answer:

the answer that you are looking for is d

Explanation:

4 0

2 years ago

Read 2 more answers

You have a solution of sugar water or<br> CeH720p(aq). What is the solute?<br> water<br> sugar

seropon [69]

Answer:Sugar

Explanation:Things being dissolved are solutes and things doing the dissolving are the solutions. So Sugar is being dissolved by water which makes sugar the solute.

3 0

3 years ago

Which process is expected to have an increase in entropy?

olganol [36]

Answer: Option (B) is the correct answer.

Explanation:

Degree of randomness of the molecules of a substance is known as entropy. More is the kinetic energy between the molecules of a substance more will be the degree of randomness.

Therefore, when a substance is present in a gaseous state then it has the maximum entropy. In liquid state, molecules are closer to each other so, there is less randomness between them.

On the other hand, in solid state molecules are much more closer to each other as they arr held by strong intermolecular forces of attraction. Therefore, they have very less entropy.

When liquid water is formed from gaseous hydrogen and oxygen molecules then gas is changing into liquid. So, there is decrease in entropy.

When $N_{2}O_{4}$ decomposes then the reaction will be as follows.

$N_{2}O_{4} \rightarrow 2NO_{2}$

Since, 1 mole is producing 2 moles. This means that degree of randomness is increasing as both the molecules are present in gaseous form.

In formation of a precipitate, aqueous solution is changing into solid state. Hence, degree of randomness is decreasing.

Rusting of iron also leads to the formation of solid as it forms $Fe_{2}O_{3}.xH_{2}O$ .

Thus, we can conclude that decomposition of $N_{2}O_{4}$ gas to $NO_{2}$ gas is the process that is expected to have an increase in entropy.

4 0

2 years ago