Chemistry, 26.10.2019 00:43 mckadams02

Dolomite is a mixed carbonate of calcium and magnesium that decomposes to co2 and the metal oxides mgo and cao upon heating. when 11.15 g of dolomite is heated, 5.70 g of mgo and cao are produced. what is percent by mass of mgco3 in the original sample of dolomite?

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Answer from: luusperezzz

The percent by mass of MgCO_3 in dolomite is 59.5 %

Explanation:

We are given:

Mass of MgO and CaO produced = 5.70 g

Mass of dolomite = 11.15 g

We know that:

Molar mass of magnesium carbonate = 84.314 g/mol

Molar mass of calcium carbonate = 100.087 g/mol

Molar mass of magnesium oxide = 40.304 g/mol

Molar mass of calcium oxide = 56.077 g/mol

Let the mass of magnesium carbonate in given sample of dolomite be 'x' grams and that of calcium carbonate be '(11.15 - x)' grams

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of magnesium carbonate = $\frac{x}{84.314}$ moles

Moles of calcium carbonate = $\frac{(11.15-x)}{100.087}$ moles

The chemical equation for the heating of magnesium carbonate follows the equation:

$MgCO_3\rightarrow MgO+CO_2$

By Stoichiometry of the reaction:

1 mole of magnesium carbonate produces 1 mole of magnesium oxide

So, $\frac{x}{84.314}$ moles of magnesium carbonate will produce = $\frac{1}{1}\times \frac{x}{84.314}=\frac{x}{84.314}mol$ of magnesium oxide

Mass of magnesium oxide = $\text{Moles of magnesium oxide}\times \text{Molar mass of magnesium oxide}$

Mass of magnesium oxide = $(\frac{x}{84.314}\times 40.304)g$

The chemical equation for the heating of calcium carbonate follows the equation:

$CaCO_3\rightarrow CaO+CO_2$

By Stoichiometry of the reaction:

1 mole of calcium carbonate produces 1 mole of calcium oxide

So, $\frac{(11.15-x)}{100.087}$ moles of calcium carbonate will produce = $\frac{1}{1}\times \frac{(11.15-x)}{100.087}=\frac{(11.15-x)}{100.087}mol$ of calcium oxide

Mass of calcium oxide = $\text{Moles of calcium oxide}\times \text{Molar mass of calcium oxide}$

Mass of calcium oxide = $(\frac{(11.15-x)}{100.087}\times 56.077)g$

We are given:

Mass of MgO and CaO produced = 5.70 g

$(\frac{x}{84.314}\times 40.304)+(\frac{(11.15-x)}{100.087}\times 56.077)=5.70\\\\0.478x+6.244-0.560x=5.70\\\\0.082x=0.544\\\\x=\frac{0.544}{0.082}=6.63g$

To calculate the mass percentage of magnesium carbonate in dolomite, we use the equation:

$\text{Mass percent of magnesium carbonate}=\frac{\text{Mass of magnesium carbonate}}{\text{Mass of dolomite}}\times 100$

Mass of dolomite = 11.15 g

Mass of magnesium carbonate = 6.63 g

Putting values in above equation, we get:

$\text{Mass percent of magnesium carbonate}=\frac{6.63g}{11.15g}\times 100=59.5\%$

Hence, the mass percent of magnesium carbonate in given amount of dolomite is 59.5 %

Answer from: Quest

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.

Answer from: Quest

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explanation:

tariffs are a tax on anything that are imported from abroad. government use them to protect and boost their local industries and the thought is that they encourage consumers to buy local instead of importing and they will hope will protect jobs and economy in the country that implements them

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Dolomite is a mixed carbonate of calcium and magnesium that decomposes to co2 and the metal oxides m...

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