Unit 1 Test: Elements, Compounds, and Solutions (ALL QUESTIONS)

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include sodium, oxygen, and gold.

Front

What are compounds?

Back

Compounds are substances formed when two or more elements chemically bond together. For example, water (H2O) is a compound made of hydrogen and oxygen.

Front

What is a solution?

Back

A solution is a homogeneous mixture of two or more substances, where one substance (the solute) is dissolved in another (the solvent). For example, saltwater is a solution of salt (solute) in water (solvent).

Front

What is the difference between a physical change and a chemical change?

Back

A physical change alters the form or appearance of a substance without changing its chemical composition (e.g., melting ice). A chemical change results in the formation of new substances (e.g., burning wood).

Front

What is the role of temperature in the rate of dissolution?

Back

Higher temperatures generally increase the rate of dissolution because they provide more energy to the particles, allowing them to break apart and mix more easily.

Front

What is the role of stirring in the rate of dissolution?

Back

Stirring increases the rate of dissolution by distributing the solute particles throughout the solvent, allowing them to interact more quickly.

Front

What is a solute?

Back

A solute is the substance that is dissolved in a solution. For example, in saltwater, salt is the solute.

Front

What is a solvent?

Back

A solvent is the substance in which the solute is dissolved to form a solution. For example, in saltwater, water is the solvent.

Front

What is the chemical formula for nitrate?

Back

The chemical formula for nitrate is NO3, which consists of one nitrogen atom and three oxygen atoms.

Front

What is an example of a chemical change?

Back

An example of a chemical change is the burning of a candle, where wax (a hydrocarbon) reacts with oxygen to produce carbon dioxide and water.