You visited us 4 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Depression in Freezing Point

A sample cont...

Question

A sample containing only CaCO₃ and MgCO₃ is ignited to CaO and MgO. The mixture of oxides produced weight exactly half as much as the original sample. Calculate the mass percentages of CaCO₃ & MgCO₃ in this sample.

Open in App

Solution

Dear student

Overall reaction is as follows:
CaCO₃ + MgCO₃ ==> CaO + MgO + 2CO₂
Let X = moles of CaCO₃
X will also equal the moles of CaO
Let Y = moles of MgCO₃
Y will also equal the moles of MgO
Molar mass of CaCO₃ = 100 g/mol
Molar mass of CaO = 56 g/mol
Molar mass of MgCO₃ = 84.3 g/mol
Molar mass of MgO = 40.3 g/mol
Total mass of reactants = 100X + 84.3Y
Total mass of oxides = 56X + 40.3Y
Mass of oxides is half as much as original sample, so
(2)(56X + 40.3Y) = 100X + 84.3Y
112X + 80.6Y = 100X + 84.3Y
12X = 3.7Y
Now let X = 1 mole and Y must be equal to 3.24 moles
Mass of CaCO₃ in sample = 100 g
Mass of MgCO₃ in sample = 273 g

Percentage of CaCO₃ in sample = (100/373) = 26.8%
Percentage of MgCO₃ in sample = (273/373) = 73.2%

Regards

Suggest Corrections

Similar questions

Q. A sample containing only

C a C O_{3}

and

M g C O_{3}

is ignited to

C a O

and

M g O

. The mixture of oxides produced weight exactly half as much as the original sample. The mass percentages of

C a C O_{3}

and

M g C O_{3}

in the sample are respectively :

A sample containing only caco3 and Mgco3 is ignited to CaO and Mgo . The mixture of oxides produced weight exactly half as much as the original sample .

Calculate the percentage of caco3 and mgco3 in the sample

Q. A

0.60 g

sample consisting of only

C a C_{2} O_{4}

and

M g C_{2} O_{4}

is heated at

500^{\circ} C

, converting the two salts of

C a C O_{3}

and

M g C O_{3}

. The sample then, weighs

0.465 g

. If the sample had been heated to

900^{\circ} C

, where the products are

C a O

and

M g O

, what would the mixtures of oxides have weighed?

Q. A

0.60 g

sample consisting of only

C a C_{2} O_{4}

and

M g C_{2} O_{4}

is heated at

500^{o} C

converting the two salts to

C a C O_{3}

and

M g C O_{3}

. The sample then weight

0.465 g

. If the sample had been heated to

900^{o} C

, where the products are

C a O

and

M g O

, what would the mixtures of oxide have weighed (in grams)?
Report your answer upto two decimal only.

Q. A

0.60 g

sample consisting of only

C a C_{2} O_{4}

and

M g C_{2} O_{4}

is heated at

500^{o} C,

converting the two salts of

C a C O_{3}

and

M g C O_{3} .

The sample then weighs

0.465 g

. If the sample had been heated to

900^{o} C

and the products are

C a O

and

M g O

, what would the mixtures of oxides have weighed?

Join BYJU'S Learning Program

A sample containing only CaCO3 and MgCO3 is ignited to CaO and MgO. The mixture of oxides produced weight exactly half as much as the original sample. Calculate the mass percentages of CaCO3 & MgCO3 in this sample.

A sample containing only CaCO₃ and MgCO₃ is ignited to CaO and MgO. The mixture of oxides produced weight exactly half as much as the original sample. Calculate the mass percentages of CaCO₃ & MgCO₃ in this sample.