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3 years ago

If 4520 kJ of heat is needed to boil a sample of water, what is the mass of the sample of water (ΔHvaporiztion = 2260kJ/kg)?

Chemistry

1 answer:

olga nikolaevna [1]3 years ago

6 0

Answer:2kg

Explanation:heat gained=heat lost

mass x 2260=4520

4530÷2260

And=2kg

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4 years ago

Solid calcium carbonate decomposes to produce solid calcium oxide and carbon dioxide gas. Express your answer as a chemical equa

Gwar [14]

Answer:

$CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$

Explanation:

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In this case, when solid calcium carbonate, CaCO3 (s), is decomposed by the action of thermal energy (heat), solid calcium oxide, CaO (s) and carbon dioxide gas, CO2 (g) are yielded via the following reaction:

$CaCO_3\rightarrow CaO+CO_2$

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3 years ago

36g of KOH dissolved in 800mL of water. What is the molality of the solution?

Bad White [126]

Answer:

0.80m of KOH

Explanation:

Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.

In the problem, the solute is KOH and solvent is water.

Moles of 36g KOH -Molar mass: 56.1g/mol- are:

36g KOH × (1mol / 56.1g) = 0.642 moles of KOH

Now, as density of water is 1g/mL, mass of 800mL of water is:

800mL × (1g / mL) × (1kg / 1000g) = 0.800kg of water

Thus, molality is:

0.642moles of KOH / 0.800kg = 0.80m of KOH

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4 years ago

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

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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;

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

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4 years ago

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