Observations That Indicate a Chemical Change
Trending Questions
Question 9
Which of the following statement is incorrect for a chemical reaction?
(a) Heat may be given out but never absorbed.
(b) Sound may be produced.
(c) A colour change may take place.
(d) A gas may be evolved.
Burning of a coal is a physical change or a chemical change?
Question 4
Which of the following is/are true when milk changes into curd?
(i) Its state is changed from liquids to semi-solid.
(ii) It changes colour.
(iii) It changes taste.
(iv) The change cannot be reversed.
Choose the correct option from below :
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i), (iii) and (iv)
(d) (i) to (iv)
a) Vinegar is mixed with baking soda. Can you get vinegar and the bicarbonate back from the resultant mixture? Is it a chemical or a physical change?
b) How can we confirm the release of carbon dioxide? [3 MARKS]
The new substances formed in a chemical reaction are called____.
When Rashi left for office in the morning she forgot to keep the packet of milk inside the refrigerator and after returning back she realized that the milk had turned sour. Can she get the fresh milk back?
Yes, it is a reversible change
No, it is an irreversible change
Cannot be determined
Depends upon the amount of milk
Which of the following is true with the conversion of milk to curd?
It is a chemical change and a reversible change.
It is a reversible change.
It is a physical change.
It involves changes in chemical composition.
Your mother daily cooks food for you from raw grains and raw vegetables. Which type of change is this?
reversible change
temporary change
physical change
chemical change
Explain why the curdling of milk is a chemical change.
When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
Which of the following is/are true when milk changes into curd? [1 mark]
(i) Its state is changed from liquids to semi-solid.
(ii) It changes colour.
(iii) It changes taste.
(iv) The change cannot be reversed.
Choose the correct option from below :
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i), (iii) and (iv)
(d) (i) to (iv)
- Heat, light or any other radiation (ultraviolet, for example) may be given off or absorbed.
- Sound may be produced.
- A change in smell may take place or a new smell may be given off.
- All of the above.
Explain why burning of wood and cutting it into small pieces are considered as two different types of changes.
Which of the following is true with the conversion of milk to curd?
It is a reversible change.
It is a chemical change and a reversible change.
It is a physical change.
It involves changes in chemical composition.
