Advertisements
Advertisements
प्रश्न
Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct ?
- P is a compound
- X and Y are compounds
- X and Y are elements
- P has a fixed composition
पर्याय
(i), (ii) and (iii)
(i), (ii) and (iv)
(ii), (iii) and (iv)
(i), (iii) and (iv)
Advertisements
उत्तर
(i), (iii), and (iv)
Statements (i), (iii), and (iv) are correct. When two elements combine in a chemical reaction to give a product, the product is a compound. Composition of a compound has a fixed ratio and its properties are different from the elements participating in the reaction.
APPEARS IN
संबंधित प्रश्न
Tick the most appropriate answer.
4. Chemical changes involve
- change in shape.
- change in size.
- change in molecular composition.
- none of these
Chemical changes are accompanied by changes in energy.
Given reason:
Cutting of a cloth piece is a physical change, though it cannot be reversed.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Slow and fast change.
Photosynthesis is a natural process by which green plants manufacture food in the presence of sunlight.
State the conclusions which can be drawn, to represent photosynthesis as a physical or a chemical change.
Select the chemical changes from the following list of changes
Drying of a fruit
State which of the following 1 to 5 pertain to – A: Physical Change B: Chemical change :
- Sublimation.
- Fermentation.
- Liquefaction or condensation.
- Magnetization.
- Respiration.
Match the examples of changes in List I with the correct type of change in List II.
| List I | List II |
| 1. Burning of paper | A: Physical change |
| 2. The ringing of an electric bell | B: Chemical change |
| 3. Curdling of milk | |
| 4. Electric light is switched on | |
| 5. Melting of butter |
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
Which of the following is not a physical change?
