Physical Science 8 | Concept 1.1 - Combining and Mixing

What is the definition of a solute?

• A substance that dissolves in a solvent to form a solution

• A substance that does the dissolving in a solution

• A mixture of two or more substances

• A chemical reaction between two elements

Answer explanation

A solute is defined as a substance that dissolves in a solvent to form a solution. This distinguishes it from the solvent, which is the substance that does the dissolving.

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DOK Level 1: Recall

Which of the following is an example of a pure substance?

• Saltwater

• Air

• Gold

• Salad

Answer explanation

Gold is a pure substance because it consists of only one type of atom, while saltwater, air, and salad are mixtures containing multiple components.

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DOK Level 1: Recall

What is the definition of a chemical reaction?

• A process where substances are mixed without changing their chemical properties

• A process that involves the rearrangement of the molecular or ionic structure of a substance

• A process of separating substances based on their physical properties

• A process of dissolving a solute in a solvent

Answer explanation

A chemical reaction is defined as a process that involves the rearrangement of the molecular or ionic structure of a substance, leading to the formation of new substances with different properties.

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DOK Level 1: Recall

What is solubility?

• The ability of a substance to conduct electricity

• The ability of a substance to dissolve in a solvent

• The ability of a substance to change its state

• The ability of a substance to react with acids

Answer explanation

Solubility refers to the ability of a substance to dissolve in a solvent, forming a solution. This is the correct choice, as it directly defines what solubility means, unlike the other options which describe different properties.

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DOK Level 1: Recall

Which of the following is a characteristic of a homogeneous mixture?

• Different components are visible

• Components are evenly distributed

• Components can be easily separated

• Components are in different phases

Answer explanation

A homogeneous mixture has components that are evenly distributed, making it appear uniform throughout. In contrast, visible components, easy separation, and different phases indicate a heterogeneous mixture.

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DOK Level 1: Recall

What is a suspension?

• A homogeneous mixture of two or more substances

• A heterogeneous mixture where particles are suspended in a fluid

• A chemical reaction between two liquids

• A solution where the solute is completely dissolved

Answer explanation

A suspension is defined as a heterogeneous mixture where solid particles are dispersed in a fluid but not dissolved. This distinguishes it from solutions and homogeneous mixtures, making the correct choice the second option.

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DOK Level 1: Recall

What is the role of a solvent in a solution?

• It is the substance that is dissolved

• It is the substance that dissolves the solute

• It is the solid part of the solution

• It is the gaseous part of the solution

Answer explanation

The solvent is the substance that dissolves the solute, making it a crucial component of a solution. It facilitates the interaction and dispersion of the solute particles, allowing for the formation of a homogeneous mixture.

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DOK Level 1: Recall

Which of the following is an example of a chemical change?

• Melting ice

• Dissolving sugar in water

• Burning wood

• Mixing sand and salt

Answer explanation

Burning wood is a chemical change because it transforms the wood into ash and gases through combustion, altering its chemical structure. In contrast, melting ice, dissolving sugar, and mixing sand and salt are physical changes.

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DOK Level 1: Recall

What is an emulsion?

• A mixture of two or more liquids that are normally immiscible

• A solid dissolved in a liquid

• A gas dissolved in a liquid

• A homogeneous mixture of gases

Answer explanation

An emulsion is specifically defined as a mixture of two or more liquids that do not normally mix, such as oil and water. This distinguishes it from other mixtures like solids in liquids or gases in liquids.

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DOK Level 1: Recall

What is the definition of a compound?

• A mixture of two or more substances

• A chemical combination of two or more elements

• A single element in its pure form

• A physical blend of substances

Answer explanation

A compound is defined as a chemical combination of two or more elements, which distinguishes it from mixtures or physical blends that do not involve chemical bonding.

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DOK Level 1: Recall