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3 years ago

Question 3 (1 point)

Chemistry

1 answer:

pentagon [3]3 years ago

5 0

Full question:

The IUPAC name for CH3CH2C≡CCH3 is:

Answer:

2-pentyne

Explanation:

To name hydrocarbons, you first you have to identify the longest carbon chain. There are 5 carbons in this chain, so we know the name is "pent".

You then have to identify the presence of any double or triple bonds. If double bonds, it is an alkene, if triple bonds, it is an alkyne. In this case there is a triple bond, so we know the hydrocarbon is pentyne.

You then number the chain to give the lowest number to the triple bond. It could either be 4 (countnig carbons from left to right) or 2 (from right to left). Therefore, the answer is 2-pentyne.

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Why aren't descriptive investigations repeatable?

Bad White [126]

In descriptive investigations, we still haven't formed any hypothesis yet so we seek information by asking question.

It's not repeatable because repeating the questions over and over again without any clue about what we want to seek is completely waste of time.

Hope this helps xox :)

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2 years ago

Read 2 more answers

Molecules of carbon dioxide are linear. What type of force exists between these molecules?

Vadim26 [7]

London Dispersion forces

Explanation:

London dispersion forces exists between the molecules of CO₂. These are weak attractions found between non-polar (and polar) molecules(symmetrical molecules).

This attraction sometimes makes non-polar molecules polar.
This is because of the uneven charge distribution caused by the constant motion of its electrons.
A temporary dipole or instantaneous dipole induces the neighboring molecules to become distorted and forms dipoles as well.
The forces are the weakest of all electrical forces.

Learn more:

Intermolecular forces brainly.com/question/10107765

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7 0

2 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

A mixture contains only nacl and al2(so4)3. a 1.45 g sample of the mixture is dissolved in water, and an excess of naoh is added

Aleks [24]

When mixture of NaCl and Al₂(SO₄)₃ is allowed to react with excess NaOH, only Al₂(SO₄)₃ reacts with it and NaCl does not react with NaOH due to presence of common ion (Na⁺). On reaction gelatinous precipitate of aluminium hydroxide [Al(OH)₃] is produced. The balanced chemical reaction is represented as-

Al₂(SO₄)₃ + 6NaOH → 2Al(OH)₃ + 3Na₂SO₄

On this reaction, 0.495 g = 0.495/78 moles =6.346 X 10⁻³ moles of Al(OH)₃.

As per balanced reaction, two moles of Al(OH)₃ is produced from one mole Al₂(SO₄)₃. So, 6.346 X 10⁻³ moles of Al(OH)₃ is produced from (6.346 X 10⁻³)/2 moles=3.173 X 10⁻³ moles of Al₂(SO₄)₃= 3.173 X 10⁻³ X 342 g of Al₂(SO₄)₃=1.085 g of Al₂(SO₄)₃.

So, mass percentage of Al₂(SO₄)₃ is= (amount of Al₂(SO₄)₃/total amount of mixture)X100 = $\frac{1.085 X 100}{1.45}$ =74.8 %.

7 0

2 years ago

What are the primary chemical components present in a phosphate buffer at ph 7.4? H3po4 and po43–?

fenix001 [56]

Answer :

The correct answer for primary component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .

Buffer solution :

It is a solution of mixture of weak acid and its conjugate base OR weak base and its conjugate acid . It resist any change in solution when small amount of strong acid or base is added .

Capacity of a good buffer :

A good buffer is identified when pH = pKa .

From Hasselbalch - Henderson equation which is as follows :

$pH = pka + log \frac{[A^-]}{[HA]}$

If [A⁻] = [HA] ,

pH = pka + log 1

pH = pKa

This determines that if concentration of weak acid and its conjugate base are changed in small quantity , the capacity of buffer to maintain a constant pH is greatest at pka . If the amount of [A⁻] or [HA] is changed in large amount , the log value deviates more than +/- 1M and hence pH .

Hence Buffer has best capacity at pH = pka .

Phosphate Buffer :

Phosphate may have three types of acid-base pairs at different pka ( shown in image ).

Since the question is asking the pH = 7.4

At pH = 7.4 , the best phosphate buffer will have pka near to 7.4 .

If image is checked the acid - base pair " H₂PO₄⁻ and HPO₄²⁻ has pka 7.2 which is near to pH = 7.4 .

Hence we can say , the primary chemical component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .

8 0

2 years ago