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3 years ago

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How many grams of zinc metal will react completely with 7.8 liters of 1.6 M HCl? Show all of the work needed to solve this probl

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Zn (s) + 2HCl (aq)yields ZnCl2 (aq) + H2 (g)

How many grams of iron metal do you expect to be produced when 298 grams of an 83.1 percent by mass iron (II) nitrate solution react with excess aluminum metal? Show all of the work needed to solve this problem.
2Al (s) + 3Fe(NO3)2 (aq)yields 3Fe (s) + 2Al(NO3)3 (aq)

1 answer:

Andru [333]3 years ago

5 0

<u>Answer:</u>

For 1: The correct answer is 407.97 grams.

For 2: The correct answer is 76.72 grams.

<u>Explanation:</u>

<u>For 1:</u>

We are given the molarity of HCl, to find the moles of HCl, we use the formula:

$Molarity=\frac{\text{Moles}{\text{Volume}}$

We are given:

Molarity = 1.6 M

Volume = 7.8 L

Putting values in above equation, we get:

$1.6mol/L=\frac{\text{Moles of HCl}}{7.8L}\\\\\text{Moles of HCl}=12.48mol$

For the given reaction:

$Zn(s)+2HCl(aq.)\rightarrow ZnCl_2(aq.)+H_2(g)$

By Stoichiometry of the reaction:

2 moles of HCl reacts with 1 mole of zinc metal.

So, 12.48 moles of HCl react with = $\frac{1}{2}\times 12.48=6.24mol$ of Zinc metal.

To calculate the mass of zinc metal, we use the formula:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Molar mass of Zinc metal = 65.38 g/mol

$6.24=\frac{\text{Mass of zinc metal}}{65.38g/mol}\\\\\text{Mass of zinc metal}=407.97g$

<u>For 2:</u>

We are given that 298 grams of 83.1 % by mass of iron (II) nitrate solution are present.

So, mass of Iron (II) nitrate solution will be = $\frac{83.1}{100}\times 298=247.638g$

Molar mass Iron (II) nitrate = 180 g/mol

Putting values in equation 1, we get:

$\text{Moles of }Fe(NO_3)_2=\frac{247.638g}{180g/mol}=1.37mol$

For the following reaction:

$2Al(s)+3Fe(NO_3)_2(aq.)\rightarrow 3Fe(s)+2Al(NO_3)_3(aq.)$

By Stoichiometry of the reaction:

3 moles of $Fe(NO_3)_2$ produces 3 moles of iron metal.

So, 1.37 moles of $Fe(NO_3)_2$ will produce = $\frac{3}{3}\times 1.37=1.37mol$ of iron metal.

To calculate the mass of zinc metal, we equation 1:

$1.37=\frac{\text{Mass of iron metal}}{56g/mol}\\\\\text{Mass of iron metal}=76.72g$

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MgCl₂

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One mole of magnesium chloride has a mass of 95.211 grams.

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2.40 x 95.211 = 228.5

To 3 sig figs this is 229.

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In the rate of reaction, A and B are the reactants and C and D are the products.

a, b, c and d are the stoichiometric coefficient of A, B, C and D respectively.

The negative sign along with the reactant terms is used simply to show that the concentration of the reactant is decreasing and positive sign along with the product terms is used simply to show that the concentration of the product is increasing.

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$2D(g)+3E(g)+F(g)\rightarrow 2G(g)+H(g)$

The expression for rate of reaction :

$\text{Rate of disappearance of }D=-\frac{1}{2}\frac{d[D]}{dt}$

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