Which statement is correct regarding physical and chemical changes?
Chemical changes alter composition
A physical change affects only the physical state, shape or appearance of a substance, while its chemical composition remains the same; melting of ice and dissolving of salt are common examples and most such changes are reversible.
A chemical change, on the other hand, involves rearrangement of atoms to form entirely new substances with different properties, as seen in rusting of iron or burning of paper, and these changes are usually irreversible.
So the key distinction is that chemical changes alter the composition of matter, whereas physical changes do not form new substances.
Hence, the correct answer is Chemical changes alter composition.
Similar Questions
Which of the following mixtures is NOT homogeneous?
Who was the first scientist to use the term 'element'?
Match the compound to its respective mass ratio by elements from the table given below.
Compound Mass Ratio by Elements 1. Water (H2O) A. 1 : 8 2. Carbon dioxide (CO2) B. 14 : 3 3. Ammonia (NH3) C. 3 : 8 4. Sulphur dioxide (SO2) D. 1 : 1 If hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), which ions from each reactant participate in forming water?
Which of the following most accurately represents a heterogeneous mixture?
Among the following, what has a molecular mass of 44 u?
When 16 g of oxygen is combined with 2 g of hydrogen, 18 g water is formed. This observation is in accordance with:
Methyl orange turns red in:
Why is the reaction flask corked during experiments verifying conservation of mass?
Which of the following is a heterogenous mixture?
Important Questions from Basic Concepts of Chemistry
- Which law states that a compound always contains the same elements in the same proportion by mass?
- Which of the following is NOT applicable to the Law of Constant Proportion?
- Which of the following best differentiates a mixture from a compound?
- Which of the following is an element?
- Which of the following best defines a heterogeneous mixture?
