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Which reaction can be used to calculate the enthalpy of formation of a substance

Zielflug [23.3K]

ANSWER

option B

EXPLANATION

Firstly, we will need to define the standard heat of formation

The standard heat of formation is the amount of heat evolved or absorbed when one mole of a compound is completely formed from its constituent elements under standard conditions.

From the options provided, you will see that only option B aligns with the definition of the standard heat of formation.

$\text{ H}_{2(g)}+\text{ }\frac{1}{2}O_2\rightarrow\text{ H}_2O(l)$

From the above reaction, you will see that 1 mole of water is formed from hydrogen and oxygen.

Hence, the answer is option B

4 0

1 year ago

Crude oil is separated into different substances such as gasoline, petroleum, diesel fuel, and propane by which process ?

algol [13]

<span>Fractionation - to expand from my answer to a previous question fractionation can be used to separate out more than one component based on a specific property. You still wanted to use Distillation on the other answer. Fractionation on this one.</span>

4 0

3 years ago

For the following reaction in aqueous solution, identify all those species that will be spectator ions. Select all that apply.

uranmaximum [27]

The reaction is incorrect. The correct reaction is: Na₂SO₄ + Hg(NO₃)₂ → HgSO₄ + 2NaNO₃. The options are:

A. Hg₂SO₄

B. Na₂SO₄

C. Na⁺

D. NO₃⁻

E. SO₄⁻²

F. Hg₂(NO₃)₂

G. NaNO₃

H. Hg⁺²

Answer:

C, D, E, H

Explanation:

The ions are formed after dissociation of the compound in the solution. When they're negatively charged, they're called anions, when they're negatively charged, they're called cations. If the ion is presented on both sides of the reaction, it is called a spectator ion.

Thus, the reaction given:

Na₂SO₄ + Hg(NO₃)₂ → HgSO₄ + 2NaNO₃

So, let's do the dissociation.

Na₂SO₄ is formed by the ions Na⁺ and SO₄⁻²;

Hg(NO₃)₂ is formed by the ions Hg⁺² and NO₃⁻;

HgSO₄ is formed by the ions Hg⁺² and SO₄⁻²;

NaNO₃ is formed by the ions Na⁺ and NO₃⁻.

Thus, the spectator ions are Na⁺, SO₄⁻², Hg⁺², and NO₃⁻.

7 0

3 years ago

The pH of a solution is measured to be pH=10. What is true of this solution?

Marta_Voda [28]

Answer:

a. the solution is a base

Explanation:

The pH range is between 0 to 14.

A solution with a pH value between 0 and 6 is said to be acidic.

A solution with pH value at 7, is said to be neutral, e.g., distilled water.

A solution with pH value between 8 and 14 is a base.

Given pH = 10, a pH value of 10 falls between the base or alkali range of the indicator

8 0

4 years ago

What alkene reacts with methanol in an acid catalyzed reaction to produce t-butyl methyl ether?a. ethyleneb. 2-methylpropenec. 2

AVprozaik [17]

Answer:

Option-B (2-methylpropene)

Explanation:

The reaction scheme is attached below,

In first step the alkene acts a nucleophile and adds H⁺ across double bond yielding a stable tertiary carbocation.

In the second step the oxygen atom of methanol acts as nucleophile and attacks the positive charge carrying carbon atom resulting in the formation of t-butyl methyl ether.

3 0

4 years ago