Molecules and compounds

Front

What are compounds?

Back

Compounds are substances formed when two or more elements chemically bond together, resulting in a substance with new properties that differ from the individual elements.

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NGSS.MS-PS1-1

Front

What is a molecule?

Back

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

Tags

NGSS.MS-PS1-1

Front

How many molecules are represented by the formula 2H₂O?

Back

The formula 2H₂O represents 2 molecules of water.

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NGSS.MS-PS1-1

Front

How many atoms of oxygen are in a molecule of carbon dioxide (CO₂)?

Back

There are 2 atoms of oxygen in a molecule of carbon dioxide (CO₂).

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NGSS.MS-PS1-1

Front

What does the coefficient in a chemical equation indicate?

Back

The coefficient indicates the number of molecules or moles of a substance involved in a chemical reaction.

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NGSS.MS-PS1-5

Front

What is the difference between an element and a compound?

Back

An element is a pure substance that cannot be broken down into simpler substances, while a compound is made up of two or more elements chemically combined.

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NGSS.MS-PS1-5

Front

What is the chemical formula for water?

Back

The chemical formula for water is H₂O.

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NGSS.MS-PS1-1

Front

What is the significance of subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule; for example, in H₂O, the '2' indicates there are 2 hydrogen atoms.

Tags

NGSS.MS-PS1-1

Front

What is the process of forming compounds from elements called?

Back

The process of forming compounds from elements is called chemical bonding.

Tags

NGSS.MS-PS1-5

Front

What type of bond forms between atoms in a molecule?

Back

Atoms in a molecule are held together by chemical bonds, which can be covalent or ionic.