Molecules, elements and compounds

Hydrogen is a pure substance represented by the chemical symbol H. Which of the following best describes hydrogen?

• Hydrogen is an element made of two or more different kinds of atoms.

• Hydrogen is a compound made of only one kind of atom.

• Hydrogen is a compound made of two or more different kinds of atoms.

• Hydrogen is an element made of only one kind of atom.

Carbon (C) and hydrogen (H) are pure substances. Each is made of only one type of atom, but carbon atoms are different from hydrogen atoms. Carbon and hydrogen chemically combine to form methane (CH4).

• methane is an element and carbon and hydrogen are compounds.
• carbon, hydrogen, and methane are all elements.
• carbon, hydrogen, and methane are all compounds.
• carbon and hydrogen are elements and methane is a compound.

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NGSS.MS-PS1-1

What is a compound?

• an atom with more electrons than protons

• a substance in which the atoms of two or more elements are combined together

• an atom with more neutrons than protons

• a substance in which the atoms of three or more elements are chemically combined together

Carbon dioxide is formed when two oxygen atoms chemically combine with a carbon atom. Which term best describes carbon dioxide?

• atom
• mixture
• element
• compound

Tags

NGSS.MS-PS1-1

What defines a mixture?

• described by a chemical formula
• can be broken down into its basic substances through physical means
• created through a chemical reaction
• cannot be broken down into simpler substances

Each ball shown in the diagram represents a type of atom. Balls of the same shade and size represent the same kind of atom. Which diagram shows a mixture?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-1

What is the picture displayed represent ?

• atom

• element

• molecule

• compound

What is the picture displayed?

• atom
• element
• molecule
• compound

Tags

NGSS.MS-PS1-1

Are these molecules also compounds?

• YES
• NO

Tags

NGSS.MS-PS1-1

Are these molecules also compounds?

• YES
• NO

Tags

NGSS.MS-PS1-1