Chemical Reaction Indicators: Change in Size
A chemical reaction signifies the formation of new substances with distinct properties. While certain observations strongly suggest a reaction has occurred, others do not reliably indicate it.
Evidence of Chemical Reactions
The following are common indicators that a chemical reaction might be happening:
- Change in colour: Often signifies the creation of new chemical compounds. For instance, metal rusting changes its colour.
- Evolution of a gas: Vigorous bubbling or fizzing points to the production of a gas, a frequent outcome of chemical changes.
- Change in state: Although state changes like melting are physical, a chemical reaction can result in a substance changing its state, for example, producing gases from solid reactants.
Evaluating Change in Size
A change in size, whether an increase or decrease, is typically characteristic of a physical change, not a chemical reaction. Examples include:
- Materials expanding or contracting due to temperature changes.
- Objects physically breaking down or eroding over time.
Because a change in size does not necessarily involve the formation of new chemical substances, it does not serve as a definitive indicator that a chemical reaction has taken place. The other options listed are more direct indicators of chemical change.
Similar Questions
- Which chemical process results in the formation of plaque on copper, the rusting of iron and the blackening of silver?
- What is oxidization?
- With which substance does silver react and turn black?
- Which of the following solutions has the highest concentration of hydrogen ions?
- Which of the following product is formed due to burning of a magnesium ribbon with a spirit lamp?
- Decomposition of calcium carbonate to calcium oxide and carbon dioxide on heating is an example of ____.
- ________ is not a chemical change.
During the electrolysis of water, hydrogen and oxygen are released in which ratio?
When dilute Hydrochloric acid (HCl) reacts with Sodium Hydrogen Carbonate (NaHCO3), which is the product formed along with Sodium chloride (NaCl) and Water (H2O)?
Which metal reacts violently with cold water, producing a metal hydroxide, hydrogen gas, and enough heat for the hydrogen to catch fire?
Important Questions from Chemical Reaction
An iron nail dipped in copper sulphate solution turns brown. This is due to which one of the following types of reactions?
Copper sulphate crystals available in the market are blue coloured crystals. By careful heating, they turn to white colour. Which one of the following is responsible for the blue colour?
Airbags work on the principle of a chemical reaction triggered by the impact producing a gaseous product that causes a sudden volume change. Which one among the following chemical conversions is responsible for this?
Which one of the following is the correct reactivity series with water?
Silver artefacts get tarnished in air due to the formation of
