Test: Classification Of Matter - Class 9 MCQ

Liquids can change their shape. Imagine water in a glass - it takes the shape of the glass it's in. That's what liquids do, they can flow and change how they look. So, liquids don't have a fixed shape like a solid object.

• The experiment with potassium permanganate and water teaches us that there are many tiny particles in matter.
• Even a few crystals of potassium permanganate can color a large volume of water, showing us that there are millions of tiny particles in just one crystal of potassium permanganate.
• These particles keep dividing into smaller and smaller particles, which is why the water continues to change color even with dilution.

Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions.

Kinetic Molecular Theory can be used to explain both Charles’ and Boyle’s Laws.

The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only.

A mixture does not have a fixed melting point, boiling point etc. On the other hand, compounds have a a fixed melting point, boiling point.

The temperature at which a solid melts to become a liquid at atmospheric pressure is called the melting point. It shows when a solid changes to a liquid.

When a substance changes directly from a solid to a gas without becoming a liquid first, we call it sublimation. It's like magic! Imagine ice turning into fog without becoming water first. That's sublimation! It's a cool way for some substances to change their states.

• Matter is made up of tiny particles that are like very small building blocks. These particles can join together to make bigger things, like how toy blocks can be put together to build a tower.
• When we dissolve a little bit of a substance in a lot of water, like when we mix a tiny bit of coloring in a big glass of water, it shows us that even a small amount of something can spread and color a large amount of water. This tells us that there are many tiny particles in just a small amount of the substance, and these particles can keep breaking into even smaller pieces.

Breathing is what living things do to take in oxygen from the air. This oxygen is needed to stay alive and keep our bodies working.

Clothes dry faster on a windy day because the fast-moving wind takes away the wetness from the clothes, making them dry quickly. So, when you see strong wind outside, that's when your clothes will dry super fast!

A compound is a substance formed when two or more elements are chemically joined. Water, salt, and sugar are examples of compounds. When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of.

Tap water is not a pure substance because it is mixed with chemicals that purify it and if it was from the ground it has naturally occurring minerals mixed in it.

Particles of matter stick together because of something called the force of attraction. It's like when magnets pull towards each other. This force is what keeps all the tiny particles together in different kinds of matter like water, air, and even solid things like a book or a toy.

When you pour nail polish remover on your palm, the liquid particles absorb energy and turn into vapor, which means they evaporate. This process makes your palm feel cool.

• When you heat up solid things like ice, they start to move more and more. Think of it like when you warm up your hands on a cold day and you start moving your fingers quickly to get warm. The same thing happens to the particles in ice when you heat them up; they start moving faster. So, the statement is True.

When the wind blows faster, water particles evaporate more quickly. It's like when you blow on your wet hands, they dry faster. So, when wind speed increases, water evaporates faster. That's why clothes dry quickly on a windy day!

An element is a simple substance that cannot be broken down into simpler substances. There are more than 100 elements found on Earth. Eg., oxygen, hydrogen, gold, silver, etc.

• In the activities we did, we learned that solids like a pen, book, needle, and wooden stick have a definite shape, distinct boundaries, and fixed volumes, but they are not easy to compress.
• It's like trying to squish a rock into a ball—it's very hard to do!
• So, the statement is False.

• Particles of matter are very active! They are like tiny, busy dancers. They are always moving, even if we can't see them moving with our eyes. When we look closely, we can see that they are always jiggling and bouncing around. This movement is what helps things like ink mix in water or the smell of incense to spread around the room. So, the statement that particles of matter are always at rest and never move is False!