Elements & Compounds

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom.

Front

What is a compound?

Back

A compound is a substance formed when two or more different elements are chemically bonded together. It has unique properties different from the individual elements.

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What is a mixture?

Back

A mixture is a combination of two or more substances that are not chemically bonded. Each substance retains its own properties.

Front

How can you identify a pure substance?

Back

A pure substance has a uniform and definite composition. It can be either an element or a compound.

Front

What is the difference between a homogeneous mixture and a heterogeneous mixture?

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A homogeneous mixture has a uniform composition throughout (e.g., saltwater), while a heterogeneous mixture has a non-uniform composition (e.g., salad).

Front

What does the chemical formula C6H12O6 represent?

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C6H12O6 represents glucose, a compound made of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.

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How many different elements are in the compound H2O?

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There are 2 different elements in H2O: hydrogen (H) and oxygen (O).

Front

What is a molecule?

Back

A molecule is the smallest unit of a chemical compound that retains its chemical properties. It consists of two or more atoms bonded together.

Front

What is the significance of the subscript in a chemical formula?

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The subscript indicates the number of atoms of each element in a molecule. For example, in H2O, the '2' indicates there are two hydrogen atoms.

Front

Why is O2 considered an element?

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O2 is considered an element because it consists of two atoms of the same element (oxygen) bonded together.