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2 years ago

Identify the most and the least acidic compound in each of the following sets.

Chemistry

1 answer:

il63 [147K]2 years ago

3 0

Answer:

See explanation

Explanation:

Our answer options for this question are:

a. 2-chlorobutanoic acid:_______ 2-chlorobutanoic acid:_______ 3-chlorobutanoic acid:______.

b. 2,4-dinitrobenzoic acid:______ p-nitrobenzoic acid:______ p-bromobenzoic acid:_______.

c. p-cyanobenzoic acid:________ benzoic acid:_______ p-aminobenzoic acid:______

We have to check each set of molecules

a. 2-chlorobutanoic acid, 3-chlorobutanoic acid

In this case, the difference between these molecules is the position of "Cl". If the chlorine atom is closer to the acid group, we will have a higher inductive effect. So, the bond O-H would be weaker and we will have more acidity. So, the molecule with more acidity is 2-chlorobutanoic acid and the less acidic would be 3-chlorobutanoic acid.

b. 2,4-dinitrobenzoic acid, p-nitrobenzoic acid, p-bromobenzoic acid

In this case, we have several structural differences. In all the structure, we have deactivating groups ( $Br$ and $NO_2$ ). If we have a deactivating group the acidity will increase. In the case of "Br", we have a weak deactivating, so, this will be the less acidic one (p-bromobenzoic acid)

in 2,4-dinitrobenzoic acid we have two deactivating groups, therefore, this would be the most acid compound.

c. p-cyanobenzoic acid, benzoic acid, p-aminobenzoic acid

On these molecules, we have several structural differences. In p-cyanobenzoic acid we have a deactivating group, therefore in this molecule we will have more acidity. In the p-aminobenzoic acid, we have an activating group, so, this would be the less acidic compound.

See figure 1

I hope it helps!

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If angle ABE = 2n + 7 and angle EBF=4n-13, find angle ABE.

andreev551 [17]

Answer:

The measure of angle ABE is 27°.

Explanation:

Consider the below figure attached with this question.

Given information: ∠ABE=2n+7 and ∠EBF=4n-13.

From the below figure it is clear that ∠ABE and ∠EBF are congruent.

$m\angle ABE=m\angle EBF$

$2n+7=4n-13$

Isolate variable terms on one side.

$7+13=4n-2n$

$20=2n$

Divide both sides by 2.

$10=n$

The value of n is 10.

We need to find the measure of ∠ABE.

$\angle ABE=2(10)+7=20+7=27$

Therefore, the measure of angle ABE is 27°.

4 0

2 years ago

For a particular reaction, ΔH∘=67.7 kJ/molΔH∘=67.7 kJ/mol and Δ????∘=126.9 J/(mol⋅K).ΔS∘=126.9 J/(mol⋅K). Assuming these values

Pavlova-9 [17]

Answer:

$T=533.49\, K$

For temperatures higher than 533.49 K we will see a spontaneous reaction, and for temperatures lower than that the reaction will not be spontaneous.

Explanation:

When are chemical reactions spontaneous? To find out we need to look at the reaction's change in Gibbs Free energy:

$\Delta G=\Delta H-T\Delta S$

When this is greater than zero, the reaction isn't spontaneous, when it is less than zero, we have a spontaneous reaction. The reaction must then change from spontaneous to non spontaneous when $\Delta G=0$ . If we insert that into our equation we get:

$0=\Delta H-T\Delta S\\\\T=\frac{\Delta H}{\Delta S}$

That is the temperature at which the reaction's spontaneity will change, plugging in our values we find:

$T=533.49\, K$

At that temperature we have $\Delta G=0$ .

Now, at a temperature greater than this one, the entropy term in our equation for the Gibbs' free energy of reaction will take over, and make $\Delta G$ , thus the reaction will be spontaneous.

On the other hand, if we lower the temperature, we will have a smaller entropy term, and we will have: $\Delta G>0$ . That is, the reaction will not be spontaneous. Therefore for temperatures higher than 533.49 K we will see a spontaneous reaction, and for temperatures lower than that the reaction will not be spontaneous.

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2 years ago

A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200

Sedbober [7]

Answer:

81°C.

Explanation:

To solve this problem, we can use the relation:

Q = m.c.ΔT,

where, Q is the amount of heat released from water (Q = - 1200 J).

m is the mass of the water (m = 20.0 g).

c is the specific heat capacity of water (c of water = 4.186 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = final T - 95.0°C).

∵ Q = m.c.ΔT

∴ (- 1200 J) = (20.0 g)(4.186 J/g.°C)(final T - 95.0°C ).

(- 1200 J) = 83.72 final T - 7953.

∴ final T = (- 1200 J + 7953)/83.72 = 80.67°C ≅ 81.0°C.

So, the right choice is: 81°C.

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2 years ago

What is the number of moles in 15.0 g AsH3?

Grace [21]

Answer:

0.192 mol.

Explanation:

To calculate the no. of moles of a substance (n), we use the relation:

n = mass / molar mass.

mass of AsH₃ = 15.0 g.

molar mass of AsH₃ = 77.95 g/mol.

∴ The number of moles in 15.0 g AsH₃ = mass / molar mass = (15.0 g) / (77.95 g/mol) = 0.192 mol.

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1 year ago

Which of the following statements best describes the Aufbau principle?

dsp73

The answer is the choice A

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2 years ago