Chemical Reactions and Their Effects

Anbesha, a grade 6 student, presents on how our world changes due to various factors like heat, light, mixing, and electricity. She explains how these factors cause physical and chemical changes in substances, using examples like photosynthesis, electromagnets, and chemical reactions. The presentation highlights both useful and harmful chemical reactions, emphasizing the impact of these changes on our environment.

What are the main factors causing changes on Earth as mentioned in the introduction?

• Sound, vibration, pressure, and density

• Gravity, magnetism, friction, and tension

• Water, air, soil, and fire

• Heat, light, mixing, and electricity

What happens to a substance when it is heated, according to the section on heat?

• It remains unchanged

• It evaporates

• It expands

• It contracts

Which of the following is an example of a combination reaction?

• Ice melting into water

• Salt dissolving in water

• Water splitting into hydrogen and oxygen

• H2 and O2 forming H2O

How does light affect silver bromide in the context of changes caused by light?

• It decomposes it into silver

• It turns it into gold

• It melts it

• It evaporates it

What role does light play in photosynthesis?

• It is absorbed as light energy

• It acts as a catalyst

• It is not required

• It provides heat energy

What happens when sulfuric acid is mixed with sugar?

• The sugar dissolves completely

• A black substance is formed

• A white substance is formed

• No new substance is formed

Which of the following is an example of a mixture where no new substance is formed?

• Copper and zinc

• Iron and sulfur

• Sugar and water

• Sulfuric acid and sugar

How does a bulb light up when electricity is applied?

• The bulb absorbs light from the surroundings

• The filament melts

• The bulb vibrates to produce light

• The filament gets heated and produces light

What is the result of passing electricity through copper sulfate solution?

• The solution evaporates

• The solution turns green

• Copper deposits on iron

• The solution becomes acidic

What is a harmful effect of chemical reactions mentioned in the video?

• They are used in digestion

• They release harmful gases

• They create new substances

• They produce energy