Pure Substances and Mixtures Quiz

Which of the following is a pure substance?

• Pizza

• Vinegar

• Salt

• Orange juice

Answer explanation

Salt is a pure substance because it consists of only one type of particle, sodium and chloride ions. In contrast, pizza, vinegar, and orange juice are mixtures containing various components.

What do all mixtures contain?

• Only one type of particle

• Two or more substances

• Water and sugar

• Atoms of a single element

Answer explanation

All mixtures contain two or more substances combined together. This distinguishes them from pure substances, which consist of only one type of particle. Therefore, the correct answer is 'Two or more substances'.

What term is also used for a homogeneous mixture?

• Mechanical mixture

• Alloy

• Solution

• Colloid

Answer explanation

A homogeneous mixture is uniformly mixed at the molecular level. The correct term for this is 'solution', which refers to a mixture where one substance is dissolved in another, unlike mechanical mixtures or colloids.

Which is a heterogeneous mixture?

• Vinegar

• Clean air

• Saltwater

• Pizza

Answer explanation

Pizza is a heterogeneous mixture because it contains various ingredients like cheese, vegetables, and meats that are not uniformly distributed. In contrast, vinegar, clean air, and saltwater are homogeneous mixtures.

What is an alloy?

• A compound made of acids

• A liquid mixture of metals

• A solid solution of two or more metals

• A mixture of gases

Answer explanation

An alloy is defined as a solid solution of two or more metals, which combines their properties to create materials with enhanced characteristics, unlike a liquid mixture or other options listed.

Which of the following is a homogeneous mixture?

• Granola

• Chocolate chip cookie

• Clean air

• Paint

Answer explanation

Clean air is a homogeneous mixture because its composition is uniform throughout, containing gases like nitrogen and oxygen evenly mixed. In contrast, granola, chocolate chip cookies, and paint have distinct components that can be identified separately.

What is the difference between homogeneous and heterogeneous mixtures?

• Only homogeneous mixtures have water

• Heterogeneous mixtures are made of gases

• Homogeneous mixtures look the same throughout

• Heterogeneous mixtures are always clear

Answer explanation

Homogeneous mixtures have a uniform composition throughout, meaning they look the same at any point. In contrast, heterogeneous mixtures have distinct, separate components that can be easily identified.

What type of mixture is fog?

• Pure substance

• Homogeneous mixture

• Heterogeneous mixture

• Compound

Answer explanation

Fog is a collection of tiny water droplets suspended in the air, making it a heterogeneous mixture. Unlike homogeneous mixtures, the components in a heterogeneous mixture can be distinguished, which is the case with fog.

Which of the following is an example of a homogeneous mixture?

• Milk

• Clear apple juice

• Muddy water

• Paint

Answer explanation

Clear apple juice is a homogeneous mixture because it has a uniform composition throughout. In contrast, milk contains fat globules, muddy water has visible particles, and paint consists of different components, making them heterogeneous.

Which gas solution is also considered a pure substance?

• Oxygen

• Air

• Steam

• Nitrogen

Answer explanation

Oxygen is a pure substance as it consists of only one type of molecule (O2). In contrast, air is a mixture of gases, and steam is water vapor, while nitrogen is a pure substance but not a gas solution.