compound/mixture/separating

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.

The chemical equation shown below represents a reaction that produces fuel for certain cars.

CO + H₂O------->CO₂ + H₂

 

Which substance in this equation is classified as an element?

• CO

• O₂

• CO₂

• H₂

Water (H₂O), is not found on the periodic table because water is a...

• atom

• compound

• liquid

• mixture

When the elements copper (Cu) and oxygen (O) chemically combine, they form...

• an ion

• a gas

• a compound

• a mixture

This image is a model of...

 

• an element

• a compound

• a homogenous mixture

• a heterogeneous mixture

This picture is a model of...

• an element

• a compound

• a homogenious mixture

•  

  a heterogeneous mixture.

Contains only one kind of atom.

• Element
• Compund
• Mixture

Contains two or more atoms combined

• Elements
• Compounds
• Mixtures

Is sugar (C₁₂H₂₂O₁₁) an element or a compound?

• Element
• Compound