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3 years ago

Calculate the mols for 4.2g of a Mg

Chemistry

1 answer:

hjlf3 years ago

8 0

Answer:

0.175mol

Explanation:

Mole of a substance can be calculated using the formula as follows:

number of moles (n) = mass (m) ÷ molar mass (MM)

According to this question, there are 4.2g of Magnesium (Mg).

Molar mass of Magnesium = 24g/mol, hence, the number of moles of 4.2g of Mg is as follows:

n = 4.2g ÷ 24g/mol

n = 0.175mol

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4). One mole of monoclinic sulfur at 25C was placed in a constant-pressure calorimeter whose heat capacity (C) was 1620 J/K. T

andre [41]

Answer: The enthalpy change of the reaction is -243 J/mol

Explanation:

The heat released by the reaction is absorbed by the calorimeter and the solution.

The chemical equation used to calculate the heat released follows:

$q=c\times \Delta T$

where,

c = heat capacity of calorimeter = 1620 J/K

$\Delta T$ = change in temperature = $0.150^oC=0.150K$ (Change remains same)

Putting values in above equation, we get:

$q=1620J/K\times 0.15K=243J$

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

For the given chemical reaction:

$S\text{ (monoclinic)}\rightarrow S\text{ (orthorhombic)}$

We are given:

Moles of monoclinic sulfur = 1 mole

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

q = amount of heat released = -243 J

n = number of moles = 1 mole

$\Delta H_{rxn}$ = enthalpy change of the reaction

Putting values in above equation, we get:

$\Delta H_{rxn}=\frac{-243J}{1mol}=-243J/mol$

Hence, the enthalpy change of the reaction is -243 J/mol

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3 years ago

HELP!! Please (: I can’t figure out the answers

MrRa [10]

I believe I know the answer to #4
ANSWER: Two moles to a first approximation
*Disclaimer* I'm pretty sure I'm right, but I could be wrong

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What is the difference between mass and weight?

Olin [163]

Explanation:

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3 years ago

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Answer:

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Explanation:

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ΔHreaction = ∑ΔHproducts - ∑ΔHreactants

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4 years ago

Calculate the mols for 4.2g of a Mg​

Calculate the mols for 4.2g of a Mg