Chapter 02 Is Matter Around Us Pure? Questions-02
Questions
1. Differentiate between homogen-eous and heterogeneous mixtures with examples.
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Answer
| Homogeneous mixture | Heterogeneous mixture |
|---|---|
| Its constituent’s particles cannot be seen easily. | Its constituent particles can be seen easily. |
| There are no visible boundaries of separation in a homogeneous mixture. | Have visible boundaries of separation between the constituents. |
| Its constituents cannot be easily separated. | Its constituents can be separated by simple methods. |
| Examples: Alloys, solution of salt in water etc. | Examples: Mixture of sand and common salt, mixture of sand and water etc. |
2. How are sol, solution and suspension different from each other?
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Answer
| Solution: | Sol (colloidal solution): | Suspension: |
|---|---|---|
| Solution or true solution is homogeneous. | Sol or colloidal solution is heterogeneous. | Suspension is also heterogeneous. |
| NO Tyndall effect. | Tyndall effect. | Tyndall effect. |
| Solute particles cannot be filtered by using a filter paper | Cannot be separated by ordinary filter paper. | It may be transparent or translucent. |
| True solution is transparent. | It may be transparent or translucent. | Separated easily by filter paper.(because of large particles) |
| Examples: Sea water, alloys, solution of lemon juice in water etc. | Examples: Milk of magnesia, cough syrup, mist, fog, clouds, smoke, mud etc. | Examples: Mixture of sand in water, mixture of chalk in water. |
3. To make a saturated solution, $36 g$ of sodium chloride is dissolved in $100 g$ of water at 293 K. Find its concentration at this temperature.
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Answer
Mass of sodium chloride (solute) $=36 g$
Mass of water (solvent) $=100 g$
We know that, mass of solution $=$ mass of solute + mass of solvent
$=36 g+100 g=136 g$
Concentration (mass percentage) of the solution
$= \frac{\text{Mass of solute}}{\text{Mass of solution}}\times 100$
$=\frac{36 g}{136 g}\times 100 = 26.47 \%$
