Activity 5.4 Let us experiment What do you observe? Class 7

Activity 5.4 Let us experiment Class 7

Activity 5.4 Let us experiment Class 7

Question 1.

What do you observe? Class 7

Answer:

Observation and conclusion:

When we add a pinch of baking soda (sodium hydrogen carbonate) to vinegar or lemon juice, bubbles of carbon dioxide gas are produced with a fizzing sound. When we pass this gas to lime water, it turns milky. Thus, in this process, new substances are formed, it is a chemical change.

Chemical equation:

Vinegar + Baking soda → Carbon dioxide + Other substances

Question 2.

Repeat the above activity using baking soda and water. Do you observe any bubble formation? Is this a physical or chemical change? Class 7

Answer:

When baking soda is mixed with water, carbon dioxide gas is formed, showing the bubble formation.

It is a chemical change, new product carbon dioxide is formed.

Baking soda + Water → Carbon dioxide + Water