Things we Make

What is matter?

• Anything that has mass and occupies space

• A type of solid

• A mixture of gases

• A form of energy

Answer explanation

Matter is defined as anything that has mass and occupies space. This includes solids, liquids, and gases, making the first choice the correct answer, while the other options are too specific or incorrect.

Which of the following is a characteristic of solids?

• They take the shape of their container

• They have fixed shape and volume

• They have no fixed shape or volume

• They can be compressed easily

Answer explanation

Solids have a definite shape and volume, meaning they do not conform to the shape of their container. This distinguishes them from liquids and gases, which can change shape and volume.

What is an example of a liquid?

• Air

• Water

• Iron

• Wood

Answer explanation

Water is a clear example of a liquid, as it flows and takes the shape of its container. In contrast, air is a gas, iron is a solid metal, and wood is a solid material, making water the correct choice.

Which of the following is a property of metals?

• They are usually poor conductors of electricity

• They are malleable and ductile

• They do not shine

• They have low density

Answer explanation

Metals are known for being malleable and ductile, meaning they can be shaped and stretched without breaking. This property distinguishes them from non-metals, which typically lack these characteristics.

What is a compound?

• A mixture of two or more elements

• A solid that cannot be separated

• A substance made of the same type of atoms

• A combination of two or more elements in a definite proportion

Answer explanation

A compound is defined as a combination of two or more elements in a definite proportion, distinguishing it from mixtures and pure substances made of the same type of atoms.

Which of the following is an example of a mixture?

• Water (H₂O)

• Calcium Carbonate (CaCO₃)

• Carbon Dioxide (CO₂)

• Air

Answer explanation

Air is a mixture of different gases, including nitrogen, oxygen, and others. In contrast, water, calcium carbonate, and carbon dioxide are pure substances with fixed compositions.

What is an alloy?

• A solid that cannot be melted

• A type of gas

• A mixture of metals or a metal with another element

• A pure substance

Answer explanation

An alloy is defined as a mixture of metals or a metal with another element, which distinguishes it from pure substances. This makes the correct choice the one that describes alloys accurately.

What is the process of separating solid components by hand called?

• Manual Separation

• Winnowing

• Centrifugation

• Filtration

Answer explanation

The process of separating solid components by hand is called Manual Separation. This method involves physically sorting materials, distinguishing it from techniques like winnowing, centrifugation, or filtration.

What is sedimentation?

• The use of a magnet to separate metals

• The settling down of solid particles in a liquid

• The process of separating liquids

• The process of heating a mixture

Answer explanation

Sedimentation refers to the process where solid particles settle down in a liquid due to gravity. This is the correct choice, as it directly describes the phenomenon of particles accumulating at the bottom of a liquid.

What is decantation?

• Heating a mixture to evaporate the liquid

• Using a centrifuge to separate components

• Separating solids from liquids using a filter

• Transferring liquid without disturbing the mixture

Answer explanation

Decantation is the process of transferring liquid from one container to another without disturbing the solid sediment at the bottom, making it the correct choice. It differs from filtration and centrifugation methods.