Atoms, molecules, pure substances, and mixtures

Which of these is an example of a mixture?

• Soup

• Glass

• Silver

• Table salt

A student studies four chemicals in a laboratory investigation.

Which chemical cannot be further broken down into other chemicals using ordinary laboratory processes?

• 3 iron Fe

• 2 water H₂O

• 1 salt NaCl

• 4 limestone CaCO₃

Which of the particle diagrams above are showing an element?

• D only

• D and B

• C only

• A, D, and B

The particles in a suspension can be___________.

• all of these

• seen with the eye or a microscope.

• separated out by gravity.

• separated our with a filter paper

Milk is considered a colloid because...

• It is a homogeneous mixture.

• It is a mixture of two or more substances that appear to be a single substance, even under a microcope.

• It contains small clumps of protein that do not settle over time.

• It is a pure substances that does not contain more than one type of chemical.

When two or more different elements are combined, a(n)_______is formed.

• atom

• compound

• new element

• electron

The chemical formula for water is H₂O. What does the formula show about each element in the compound?

• the charge of the compound

• the number of atoms of each element

• the mass of protons in each atom

• the number of valence electrons

Which of these elements is NOT found in the compound H₂SO₄?

• oxygen

• hydrogen

• sodium

• sulfur

Which is a compound?

• ammonia (NH₃)

• Neon (Ne)

• Nitrogen (N₂)

• Ozone (O₃)

What number and types of atoms occur in a formula uit of Ca(NO₃)₂?

• 1 calcium atom, 2 neon atoms, and 3 oxygen atoms

• 1 carbon atom, 1 neon atom, and 6 oxygen atoms

• 1 calcium atom, 1 nitrogen atoms, and 3 oxygen atoms

• 1 calcium atom, 2 nitrogen atoms, and 6 oxygen atoms