Extended and Pure Substances

Which of the following is NOT a pure substance?

• copper

• water

• aspirin

• sand

Which statement(s) best describe why table sugar is considered a pure substance? (check all that apply)

• Sugar cannot be separated further by physical means

• Sugar is solid like all other pure substances

• sugar has the same chemical composition throughout

• Sugar is a mixture of compounds

• A bowl of sugar contains only one compound

Milk is uniformly mixed, it contains several compounds--water, proteins, fats, and sugars. Is milk considered a substance or a mixture?

• It is a mixture that can be separated by physical means

• it is a liquid substance with uniform composition

• it contains compounds and is therefore a substance

• it is a mixture, only solids are pure substances

A pure substance can be separated into components by physical methods

• true

• false

All samples of a specific substance have the same chemical composition

• true

• false

Aspirin is a mixture of different compounds

• true

• false

Salt is a pure compound

• yes

• no

Substances may either be elements or compounds

• true

• false

Which of the following is a pure substance? 

• Water
• Salad
• Chocolate milk
• All of them 

Which of the following is a pure substance? 

• Soil 
• Salt
• Water and sand
• Vanilla ice cream with chocolate