You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Concentration Terms - An Introduction (w/w etc)

A sample of c...

Question

A sample of chalk contains clay as impurity. The clay impurity loses $11 %$ of its weight as moisture on prolong heating. $5$ gram sample of chalk on heating shows a loss is weight (due to evolution of $C O_{2}$ and water) by $1.1 g$ . Calculate $%$ of chalk $(C a C O_{3})$ in the sample.

Open in App

Solution

Let the mass of chalk in 5g be x grams,
Therefore, mass of clay = (5 - x) grams.
Mass of moisture lost by clay = (5 - x) x $\frac{11}{100}$
= (0.55 - 0.11x) grams.
Now,
$C a C O_{3} H e a t - ----- \to C a O + C O_{2} ↑$
Molar mass of $C a C O_{3}$ is 100g, loss its mass by 44 g in the form of $C O_{2}$ gas
Therefore,
44 g of $C O_{2}$ is lost by 100 g chalk
So,
x gram $C O_{2}$ is lost by $\frac{44}{100}$ is multiplied by x = 0.44x grams
Total mass lost from 5 g of chalk/clay = 1.1g
Therefore,
(0.55 - 0.11x) + 0.44x grams = 1.1g
0.33x = 1.1 - 0.55
0.33x = 0.55
x = 1.67g
Hence, % of chalk in sample = $\frac{1, 67}{5}$ x 100
= 33.4 %
Chalk $(C a C O_{3})$ release $C O_{2}$ on heating.
33% $C O_{2}$ IS LOSS

Suggest Corrections

Similar questions

Q. A sample of chalk contained as an impurity, a form of clay which loses

14.5 %

of its mass of water on prolonged heating.

5

g of chalk on heating shows a loss of

1.507

g in mass (due to an evolution of

C O_{2}

and water). The

%

of chalk in the sample is:
(to the closest integer)

Q. A sample of calamine ore

(Z n C O_{3})

contains clay as an impurity which is

37.5

%. Clay impurity loses some amount of its weight as moisture on prolonged heating. If the total loss in weight of ore on heating (due to

C O_{2}

and

H_{2} O

) is

28

%, then find the percentage loss in the weight of the clay.

[Given: Atomic mass of

Z n = 65, C = 12, O = 16

]

Q. Clay found in a lake at Bhopal contains 15% by mass moisture along with

C a C O_{3}

and non volatile

S i O_{2}

. This on heating loses a part of its moisture, but

C a C O_{3}

is completely converted into CaO. The partially dried sample now contains 7.3% moisture and 51.5%

S i O_{2}

. What is the mass percentage of

C a C O_{3}

in the original sample of clay approximately?

Q. When

1.25 g

of a sample of chalk is strongly heated,

0.44 g

{C O}_{2}

gas in produce. Determine the percentage of pure

C a {C O}_{3}

in the chalk sample.

$6.2$ g of a sample containing $N a_{2} C O_{3}, N a H C O_{3}$ and non-volatile inert impurity on gentle heating loses $5 %$ of its weight due to reaction as shown below:

$2 N a H C O_{3} \to N a_{2} C O_{3} + H_{2} O + C O_{2}$

Residue is dissolved in water and formed $100$ mL solution and its $10$ mL portion requires $7.5$ mL of $0.2 M$ aqueous solution of $B a C l_{2}$ for complete precipitation of carbonates. Determine the weight (in g) of $N a_{2} C O_{3}$ in the original sample (as nearest integer).

Join BYJU'S Learning Program

A sample of chalk contains clay as impurity. The clay impurity loses 11% of its weight as moisture on prolong heating. 5 gram sample of chalk on heating shows a loss is weight (due to evolution of CO2 and water) by 1.1 g. Calculate % of chalk (CaCO3) in the sample.

A sample of chalk contains clay as impurity. The clay impurity loses $11 %$ of its weight as moisture on prolong heating. $5$ gram sample of chalk on heating shows a loss is weight (due to evolution of $C O_{2}$ and water) by $1.1 g$ . Calculate $%$ of chalk $(C a C O_{3})$ in the sample.