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3 years ago

AHP for the formation of rust (Fe2O3) is -826 kJ/mol. How much energy is

Chemistry

1 answer:

mars1129 [50]3 years ago

6 0

Answer:

A- 25.9 kJ

Explanation:

ΔH of formation is defined as the amount of energy that is involved in the formation of 1 mole of substance.

ΔH of rust is -826kJ/mol, that means when 1 mole of rust is formed, there are released -826kJ.

Moles of 5.00g of Fe₂O₃ (Molar mass: 159.69g/mol) are:

5.00g ₓ (1 mole / 159.69g) = 0.0313 moles of Fe₂O₃.

If 1 mole release -826kJ, 0.0313 moles release:

0.0313 moles ₓ (-826kJ / 1 mole) = -25.9kJ

Thus, heat involved is:

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4. To how much water should 50 mL of 12 M hydrochloric acid be added to

Novosadov [1.4K]

Answer : The volume of water added are, 15 mL

Explanation :

Formula used :

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the initial molarity and volume of HCl.

$M_2\text{ and }V_2$ are the final molarity and volume of water.

We are given:

$M_1=12M\\V_1=50mL\\M_2=40M\\V_2=?$

Putting values in above equation, we get:

$12M\times 50mL=40M\times V_2\\\\V_2=15mL$

Hence, the volume of water added are, 15 mL

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3 years ago

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2 years ago

Curious Carl and his lab partner were handed a 2 liter sealed flask containing two gases, neon and argon. The partial of each ga

stiv31 [10]

Answer:

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3 years ago

How many moles of chloride ions are there in 2 moles of calcium chloride?

Oksana_A [137]

Answer:

There are 4 moles of chloride ions in 2 moles of calcium chloride.

Explanation:

Start by writing the chemical formula of calcium chloride.

The suffix -ide in chloride means that chlorine is working as the ion Cl⁻, this is with oxidation state -1.

Calcium, being an alkaline earth metal, uses oxidation state +2, Ca²⁺

Then, two atoms of Cl are combined with one atom of calcium, because in this way each Cl atom will accept one electron from a Ca atom, which will donate its two valence electrons.

That is indicated in the chemical formula with subscripts: CaCl₂, meaning that each formula-unit of calcium chloride has 2 ions of chlorine and 1 ions of calcium, or twice the number of moles of chloride ion.

1 mol CaCl₂ : 1 mol Ca⁺ : 2 mol Cl⁻

⇒ 2 mol CaCl₂ : 2 mol Ca⁺ : 4 mol Cl⁻

Hence, there are 4 moles of chloride ions in 2 moles of calcium chloride.

6 0

3 years ago

If 448.85 mg of KOH is dissolved in 400 ml of water, what will be the pH of the solution?

emmasim [6.3K]

I have provided the steps and solution within the attachment. The pH of the solution would be 12.30, this indicates that the solution is basic, as a higher value of pH indicates presence of more hydroxide ions and less of hydrogen ions in the solution.

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4 years ago