Understanding Mixtures: Homogeneous vs Heterogeneous

What separation technique could be where the 1 is located?

• Distillation

• Evaporation

• Filtration

• Sieve

Answer explanation

The correct choice is 'Sieve' because it is a separation technique that physically separates particles based on size, which aligns with the context of the question. Distillation, evaporation, and filtration involve different principles.

What is a mixture?

• A substance made of two or more elements chemically combined.

• A combination of two or more substances that are not chemically bonded.

• A pure substance with a fixed composition.

• A single element in its pure form.

Answer explanation

A mixture is defined as a combination of two or more substances that are not chemically bonded, distinguishing it from compounds where elements are chemically combined.

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

• Sand and water

• Oil and water

• Salt dissolved in water

• A salad

Answer explanation

A homogeneous mixture has a uniform composition. Salt dissolved in water forms a solution where the salt is evenly distributed, making it homogeneous. In contrast, sand and water, oil and water, and a salad are heterogeneous mixtures.

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

• Air

• Vinegar

• Sugar solution

• Granite

Answer explanation

Granite is a heterogeneous mixture because it consists of different minerals that can be seen and identified separately, unlike air, vinegar, and sugar solution, which are homogeneous mixtures.

What is a key characteristic of a homogeneous mixture?

• The components are visibly distinct.

• The composition is uniform throughout.

• It can be separated by physical means.

• It contains only one type of molecule.

Answer explanation

A key characteristic of a homogeneous mixture is that the composition is uniform throughout, meaning the individual components are not visibly distinct and are evenly distributed.

Which separation technique is commonly used to separate a homogeneous mixture?

• Filtration

• Distillation

• Sieving

• Magnetic separation

Answer explanation

Distillation is used to separate homogeneous mixtures based on differences in boiling points. It effectively separates liquids in a solution, making it the correct choice for this type of mixture.

Which separation technique is suitable for separating a heterogeneous mixture?

• Evaporation

• Chromatography

• Filtration

• Crystallisation

Answer explanation

Filtration is suitable for separating heterogeneous mixtures because it allows solid particles to be separated from liquids or gases based on size, effectively isolating different components.

What property allows for the separation of mixtures by distillation?

• Solubility

• Density

• Boiling point

• Magnetism

Answer explanation

Distillation separates mixtures based on differences in boiling points. Substances with lower boiling points vaporize first, allowing for their collection and separation from those with higher boiling points.

Which of the following is a property of mixtures?

• They have a fixed melting point.

• They are always colourless.

• They can be separated into their components by physical means.

• They are always in the gaseous state.

Answer explanation

Mixtures can be separated into their components by physical means, such as filtration or distillation. This distinguishes them from pure substances, which have fixed properties and cannot be separated physically.

Which of the following is NOT a property of a homogeneous mixture?

• Uniform composition

• Components are indistinguishable

• Can be separated by physical means

• Components are easily visible

Answer explanation

A homogeneous mixture has a uniform composition and indistinguishable components. If components are easily visible, it indicates a heterogeneous mixture, making 'components are easily visible' the correct choice.