Elements, Compounds, and Mixtures

Front

What is a mixture?

Back

A mixture is a combination of two or more substances that are not chemically bonded. Examples include air, salad, and lemonade.

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What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include hydrogen (H), oxygen (O), and copper (Cu).

Front

What is a compound?

Back

A compound is a substance formed when two or more elements are chemically bonded together. Examples include water (H2O) and carbon dioxide (CO2).

Front

How many elements are in the periodic table?

Back

As of now, there are 118 known elements in the periodic table.

Front

What is the most abundant gas in Earth's atmosphere?

Back

Nitrogen is the most abundant gas in Earth's atmosphere, making up about 78%.

Front

What is a homogeneous mixture?

Back

A homogeneous mixture is a mixture that has a uniform composition throughout. An example is lemonade.

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What is a heterogeneous mixture?

Back

A heterogeneous mixture is a mixture where the components can be seen and are not uniform. An example is a salad.

Front

What is the chemical symbol for copper?

Back

The chemical symbol for copper is Cu.

Front

Can elements exist in different forms?

Back

Yes, elements can exist in different forms called allotropes. For example, carbon can exist as diamond or graphite.

Front

What is the difference between a compound and a mixture?

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A compound is a chemical combination of elements, while a mixture is a physical combination of substances.