Vedika got very confused when she fund that as the candle burnt, it melted, became smaller and heat light and carbon dioxide was produced. A decomposition reaction also yields either two or more substances. Can you explain why they are different and why are they termed as chemical changes ?
[3 MARKS]

Open in App

Solution

Explanation: 3 Marks

Combustion reactions, such as a burning candle, are examples of the chemical change through the combination of wax and oxygen in a reaction that produces heat, light, and carbon dioxide. Decomposition which is the opposite of combination, occurs when a single substance breaks down into two or more different substances.For example, baking powder consists of Sodium bi carbonate When it is heated above about 80°C it, begins to break down, forming sodium carbonate, water and carbon dioxide. In both the cases the products are different from the reactants, so they aretermed as chemical changes.

Suggest Corrections

Similar questions

Q. Which of the following happens when a wax candle is burnt?
A. Wax undergoes oxidation.
B. Heat and light energy are released.
C. Water vapour and carbon dioxide are released.

Q. Name and explain the changes that occur when a candle is burnt? [3 MARKS]

Q. Assertion :The burning of a candle is both a physical and a chemical change. Reason: Burning of candle melts the wax and hence physical state of wax has changed from solid to liquid. Again the wax combines with the atmosphere oxygen and changes to carbon dioxide, heat and light.

When wax is burnt (in the form of a wax candle), then water and carbon dioxide are formed.This shows the "change in state" characteristic of reactions.

Q. When

3 g

of carbon is burnt in

8 g

of oxygen,

11 g

of carbon dioxide is produced. What mass of carbon dioxide will be formed when

3 g

of carbon is burnt in

50 g

oxygen?

Join BYJU'S Learning Program