Unit 2A - Mixtures versus Pure Substances

sodium (Na)

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

The chemical symbol (Na) automatically makes this a pure substance. It only has one capital letter (N), so that makes it an element.

Tags

NGSS.MS-PS1-1

distilled water (H₂O)

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

The chemical symbol (H₂O) automatically makes this a pure substance. It has more than one capital letter (H and O), so that makes it a compound.

Tags

NGSS.MS-PS1-1

pond water

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

There is no chemical symbol and no chemical formula, so that automatically makes it a MIXTURE. You can see differences in the liquid, so that makes it a HETEROgeneous mixture.

Tags

NGSS.MS-LS2-3

garden soil

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

There is no chemical symbol and no chemical formula, so that automatically makes it a MIXTURE. You can see differences in the soil, so that makes it a HETEROgeneous mixture.

Tags

NGSS.MS-PS1-1

strong black coffee (really, really dark black)

• pure substance

• heterogeneous mixture
• homogeneous mixture

Answer explanation

There is no chemical symbol and no chemical formula, so that automatically makes it a MIXTURE. You can't see differences in the liquid, but a beam of light CANNOT shine through it (the light bounces off the globs of coffee bean oil), so that makes it a HETEROgeneous mixture.

oxygen (O)

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

The chemical symbol (O) automatically makes this a pure substance. It only has one capital letter (O), so that makes it an element.

ethanol (C₂H₅OH)

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

The chemical symbol (C₂H₅OH) automatically makes this a pure substance. It has more than one capital letter (C, H, O, H), so that makes it a compound.

Tags

NGSS.MS-PS1-1

carbon dioxide (CO₂)

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

The chemical symbol (CO₂) automatically makes this a pure substance. It has more than one capital letter (C and O), so that makes it a compound.

Tags

NGSS.MS-PS1-1

cake batter

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

There is no chemical symbol and no chemical formula, so that makes it a MIXTURE. You can't see differences in the liquid, but a beam of light CANNOT shine through it, so that makes it a HETEROgeneous mixture.

chicken noodle soup

• pure substance

• homogeneous mixture
• heterogeneous mixture

Answer explanation

There is no chemical symbol and no chemical formula, so that automatically makes it a MIXTURE. You can see different ingredients in the soup, so that makes it a HETEROgeneous mixture.