Atoms in molecules share pairs of electrons when they make

• polymers
• covalent bonds.
• ionic bonds.
• hydrogen bonds.

What gives water many properties that are important to living things?

• specific heat
• temperature
• hydrogen bonds
• density

Which of the following solutions has the highest H+ ion concentration?

• a solution with a pH of 10
• a solution with a pH of 7
• a solution with a pH of 4
• a solution with a pH of 1

Which of the following solutions has the lowest H+ ion concentration?

• a solution with a pH of 10
• a solution with a pH of 7
• a solution with a pH of 4
• a solution with a pH of 1

Both animal fats and plant oils are made up of glycerol and

• saturated fats.
• phospholipids.
• fatty acids.
• polar molecules.

How do ions form?

• Atoms gain or lose electrons.
• Atoms combine to make a larger atom.
• Two atoms share electrons.
• Atoms form covalent bonds.

Which substance represented in the figure (A or B) is the solute?

• substance A
• substance B
• both A and B
• neither A nor B

Identify the reactants in this reaction: 6H2O + 6CO2 → C6H12O6+ 6O2.

• 6H2O and 6CO2
• 6CO2 and C6H12O6
• 6H2O, C6H12O6, and 6O2
• C6H12O6 and 6O2

The activation energy needed for a chemical reaction is decreased by a

• substrate.
• catalyst.
• reactant.
• product.

Which property of carbon makes it the “building block of life”?

• its hydrogen bonding
• its covalent bonding
• its ability to dissolve substances
• its specific heat