CLASS-7 SCIENCE DIAGNOSTIC TEST L-4

Which of the following is a pure substance?

• Salt

• Tea

• Air

• Milk

A molecule of water is made up of...

• 2 hydrogen atoms and 1 oxygen atom

• 2 oxygen atoms and 1 hydrogen

• 3 oxygen

• Only hydrogen

A molecule is the smallest unit of a _______ that retains its properties.

Which of these describes a sour taste correctly?

• Base

• Acid

• Salt

• Compound

Which of the following is slippery to touch?

• Vinegar

• Sugar

• Soap solution

• Salt water

Litmus paper is used to test the (a)   of substances.

• color

• size

• nature

• temperature

Which statement best defines an indicator?

• It reacts with metals

• It changes color in acids/bases

• It smells sweet

• It dissolves in water

Which of these are natural materials?

• Lemon

• Turmeric

• Plastic

• China Rose

Which of these is synthetic?

• Onion

• Methyl Orange

• Turmeric

• Vinegar

Why should we not taste unknown substances in the lab?

• They may smell bad

• They might be harmful

• They may be expired

• They're too hot