SATHEE: Some Basic Concepts Of Chemistry Question 131

Some Basic Concepts Of Chemistry Question 131

Question: A 0.70 g sample consisting $C a C_{2} O_{4}$ and $M g C_{2} O_{4}$ is heated at $300^{\circ} C,$ converting the two salts of $C a C O_{3}$ and $M g C O_{3}$ . The sample when weighs 0.47 g. If the sample had been heated to $700^{\circ} C$ where the products are CaO and MgO. What would be the weight of mixture of oxides?

Options:

A) 0.36 g

B) 0.14 g

C) 0.28 g

D) 1.08 g

Show Answer

Answer:

Correct Answer: C

Solution:

[c] Idea. While solving this problem, students are advised to use the mole concept and stoichiometry as follows Consider arbitrary mass of $M g C_{2} O_{4}$ and $C a C_{2} O_{4} (0.7 - x)$ and x respectively Write the chemical reaction and calculate weight of both species. Finally using information provided in question complete the further calculation. Let x g = weight of $C a C_{2} O_{4}$ So, wt. of Mg $C_{2} O_{4} = (0.7 - x) g$

$C a C_{2} O_{4} \overset{Δ}{\to} C a C O_{3} + C O_{2}$

$M g C_{2} O_{4} \overset{Δ}{\to} M g C O_{3} + C O_{2}$ Weight of $C a C O_{3}$ produced $= \frac{x}{128} \times 100$ Weight of $M g C O_{3}$ produced $= \frac{0.7 - x}{112} \times 84$

$\frac{x}{128} \times 100 + \frac{0.7 - x}{112} \times 84 = 0.47$

$x = 0.46 g$ Mol. wt. $C a C O_{3} = 100,$ $M g C O_{3} = 84,$ $C a C_{2} O_{4} = 128,$ $M g C_{2} O_{4} = 112$ Due to further heating $C a C O_{3} \overset{Δ}{\to} \underset{\frac{x}{128}}{C a O}, + C O_{2}$

$M g C O_{3} \overset{Δ}{\to} \underset{\frac{7 - x}{112}}{M g O}, + C O_{2}$ Weight of $C a O$ and $M g O$

$= \frac{0.46}{128} \times 56 + \frac{0.24}{112} \times 40$

$= 0.20 + 0.0857$ = 0.28 g

Some Basic Concepts Of Chemistry Question 131

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Some Basic Concepts Of Chemistry Question 131

Question: A 0.70 g sample consisting CaC2O4 and MgC2O4 is heated at 300∘C, converting the two salts of CaCO3 and MgCO3 . The sample when weighs 0.47 g. If the sample had been heated to 700∘C where the products are CaO and MgO. What would be the weight of mixture of oxides?

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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