Elements, Compounds and Mixtures

Which of the following is an example of the formation of a mixture?

• Rust forming on an iron nail.

• Sugar crystals dissolving in water.

• Sodium and chlorine forming table salt.

• Hydrogen and oxygen reacting to produce oxygen.

Which statement identifies why oxygen is classified as a pure substance and air is classified as a mixture?

• Oxygen is more reactive than air.

• Oxygen has a higher density than air.

• Oxygen goes under a phase change, whereas air is always a gas.

• Oxygen contains only one substance, but air contains several substances.

Which of the following represents an element?

• H₂O
• H₂
• NaCl
• CaCO₃

Tags

NGSS.MS-PS1-1

Which of the following is not a compound?

• HCl
• Cl
• NaCl
• CO2

Tags

NGSS.MS-PS1-1

Salt has a chemical formula of NaCl.  Salt is a...

• Compound
• Element
• Mixture
• None of the Above

Tags

NGSS.MS-PS1-1

What cannot be broken down into other substances?

• Compound
• Mixture
• Solids
• Element

What is made up two or more elements that are chemically combined?

• Element
• Mixture
• Compound
• Solids

Tags

NGSS.MS-PS1-1

How many elements are represented in the compound?
Na₂CO₃

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-1

A combination of substances that are not chemically combined is called a(n)____________. 

• mixture
• compound
• physical

An element is made up of only one kind of _____.

• isotope
• plastic
• atom
• metal

Tags

NGSS.MS-PS1-1