Advertisements
Advertisements
Question
100 mL of water at room temperature of 25°C is taken in a beaker and a little of solid S is dissolved in it by stirring to obtain a solution X. More and more of solid S is added to the solution with constant stirring, while keeping the temperature of solution constant at 30°C. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker.
- The contents of beaker are filtered through a filter paper to obtain solution Y in the form of a filtrate.
- What name is given to solutions like X ?
- What name is given to solutions like Y ?
- What will you observe if the solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice ? Why ?
- What term is used to denote the amount of solid dissolved in 100 grams of water in a solution lie Y ?
Solution
- X type of solutions is known as unsaturated solution.
- Y type of solutions is known as saturated solution.
- If solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice, some of the dissolved parts of the solid will separate from the solution and will settle at the bottom of the beaker as crystals. This occurs because of the decrease in the solubility of solids and reduction in temperature.
- Solubility refers to the amount of a solid dissolved in 100 grams of water.
APPEARS IN
RELATED QUESTIONS
Match the following
| Column A | Column B | ||
| (a) | Molecules | (i) | Water boils |
| (b) | 100° C | (ii) | Evaporation |
| (c) | 0° C | (iii) | Changes from solid to gas |
| (d) | At all temperatures | (iv) | Matter |
| (e) | Camphor | (v) | Water freezes |
A kind of matter which can sublime is
Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into
(i) osmosis, and (ii) diffusion :
- swelling up of a raisin on keeping in water
- spreading of virus on sneezing
- earthworm dying on coming in contact with common salt
- shrinking of grapes kept in thick sugar syrup
- preserving of pickles in salt
- spreading of smell of cake being baked in the kitchen
- aquatic animals using oxygen dissolved in water during respiration
An inflated balloon full of air goes down slowly (becomes smaller and smaller slowly) even though the knot at the mouth of the balloon is airtight. And after a week all the air has escaped from the balloon. Explain how the air particles got out of the balloon.
Name the property which enables metals to be drawn into wires.
Classify the following into elements and compounds :
- H2O
- He
- Cl2
- CO
- Co
What are the two types of pure substances? Give one example of each type.
What are the three groups into which all the elements can be divided ? Name two elements belonging to each group.
Name a metal which has a low melting point.
Define solvent.
In what respects does a true solution differ from a colloidal solution ?
How will you test whether a given solution is a colloidal solution ?
Differentiate between a saturated and an unsaturated solution. How will you test whether a given solution is saturated or not ?
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Which technique is used in a washing machine to squeeze out water from wet clothes while drying ?
How is scrap iron separated from a heap of waste materials in factories?
Name the metals that are used in jewellery.
Celsius scale is a scale of temperature in which zero represents the melting point of ice and 100 represents the boiling point of water.
Boiling refers to the process by which a substance changes from the liquid to the gaseous state at its ______ point.
______ is used for industrial refrigeration and transporting frozen food.
