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3 years ago

NaCl has a mc020-1.jpgHfus = 30.2 kJ/mol. What is the mass of a sample of NaCl that needs 732.6 kJ of heat to melt completely?

Chemistry

2 answers:

Sidana [21]3 years ago

8 0

Answer:

d.) 1417.7 on edge 2020

Explanation:

hope this helps!

lilavasa [31]3 years ago

5 0

Answer: The mass of the sample will be 1417.7 grams.

Explanation:

We are given:

$\Delta H_{fusion}=30.2kJ/mol$

This means that 1 mole of NaCl has an enthalpy of fusion of 30.2 kJ

1 mole of NaCl has a mass of 58.44 grams.

So, 30.2 kJ of heat is require for a mass 58.44 grams of NaCl

So, 732.6 kJ of heat will be required for = $\frac{58.44g}{30.2kJ}\times 732.6 kJ$ = 1417.65 grams of NaCl.

Hence, the mass of NaCl sample will be 1417.7 grams.

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In Part III, the phenolphthalein indicator is used to monitor the equilibrium shifts of the ammonia/ammonium ion system. The phe

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The pink color in the solution fades. Some of the colored indicator ion converts to the colorless indicator molecule.

<h3>Explanation</h3>

What's the initial color of the solution?

$\text{NH}_4\text{Cl}$ is a salt soluble in water. $\text{NH}_4\text{Cl}$ dissociates into ions completely when dissolved.

$\text{NH}_4\text{Cl} \; (aq)\to {\text{NH}_4}^{+} \; (aq) +{\text{Cl}}^{-} \; (aq)$ .

The first test tube used to contain $\text{NH}_4\text{OH}$ . $\text{NH}_4\text{OH}$ is a weak base that dissociates partially in water.

$\text{NH}_4\text{OH} \; (aq) \rightleftharpoons {\text{NH}_4}^{+} \;(aq)+ {\text{OH}}^{-} \; (aq)$ .

There's also an equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ ions.

${\text{OH}}^{-}\;(aq) + {\text{H}_3\text{O}}^{+} \;(aq) \to 2\; \text{H}_2\text{O} \;(l)$ .

$\text{OH}^{-}$ ions from $\text{NH}_4\text{OH}$ will shift the equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ to the right and reduce the amount of ${\text{H}_3\text{O}}^{+}$ in the solution.

The indicator equilibrium will shift to the right to produce more ${\text{H}_3\text{O}}^{+}$ ions along with the colored indicator ions. The solution will show a pink color.

What's the color of the solution after adding NH₄Cl?

Adding $\text{NH}_4\text{Cl}$ will add to the concentration of ${\text{NH}_4}^{+}$ ions in the solution. Some of the ${\text{NH}_4}^{+}$ ions will combine with $\text{OH}^{-}$ ions to produce $\text{NH}_4\text{OH}$ .

The equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ ions will shift to the left to produce more of both ions.

${\text{OH}}^{-}\;(aq) + {\text{H}_3\text{O}}^{+} \;(aq) \to 2\; \text{H}_2\text{O} \;(l)$

The indicator equilibrium will shift to the left as the concentration of ${\text{H}_3\text{O}}^{+}$ increases. There will be less colored ions and more colorless molecules in the test tube. The pink color will fade.

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3 years ago

Given the equation: HCl + Na2SO4 → NaCl + H2SO4, if you start with 8 moles of hydrochloric acid, how many grams of sulfuric acid

Simora [160]

Answer:

392g sulfuric acid are produced

Explanation:

Based on the balanced equation:

2HCl + Na2SO4 → 2NaCl + H2SO4

2 moles of HCl produce 1 mole of sulfuric acid

To solve the problem we need to find the moles of sulfuric acid produced based on the chemical equation. Then, using its molar mass -Molar mass H2SO4 = 98g/mol- we can find the mass of sulfuric acid produced:

Moles sulfuric acid:

8mol HCl * (1mol H2SO4 / 2mol HCl) = 4 mol H2SO4

Mass sulfuric acid:

4mol H2SO4 * (98g / mol) =

392g sulfuric acid are produced

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2 years ago

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Kisachek [45]

There are four main types of air pollution sources:

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2 years ago

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AnnyKZ [126]

Answer: Option (4) is the correct answer.

Explanation:

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The chemical reaction for the same will be as follows.

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Thus, we can conclude that $CaSO_{4}$ salt is produced when sulfuric acid and calcium hydroxide react completely.

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2 years ago

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marusya05 [52]

Answer:

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Explanation:

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