What do atoms connected by covalent bonds share?

• hydrogen ions

• ionic compounds

• pairs of electrons

• carbon and oxygen

The diagram shows the particles that make up an atom. What is the name of the negatively charged particles shown in this model of an atom?

• prions

• protons

• neutrons

• electrons

From the information that two atoms have two different proton counts, you can conclude that the atoms __________.

• belong to two entirely different elements

• represent different isotopes of one element

• are likely to react violently with each other

• might be different ions of the same element

The diagram shows both a chemical change and a physical change. Which statement is supported by the diagram?

• Atoms of most elements become less stable when they bind to form compounds.

• Compounds can most easily form between elements that have full outer energy levels.

• Compounds can have different properties than the elements that make up the compound.

• Two elements will always combine in the same ratios when they react to form a compound.

ATP (adenosine triphosphate) stores energy in the bonds between its __________.

• nucleotides

• carbon atoms

• hydrogen atoms

• phosphate groups

What do light-independent reactions of photosynthesis need?

• water

• oxygen

• cellulose

• carbon dioxide

Which of these is the site of the photosystems in the light-dependent reactions of photosynthesis?

• stroma

• ATP synthase

• thylakoid membrane

• mitochondrial matrix

Which chemical equation best represents the process of photosynthesis?

• 6CO2 + 6H2O → C6H12O6 + 6O2

• C6H12O6 + 6O2→ 6CO2 + 6H2O

• C6H12O6 + 6H2O → C6H12O6 + 6O2

• 6CO2 + O2 → C6H12O6 + 6O2 + H2O

Which statement accurately describes the graph?

• Reaction 2 occurs faster than Reaction 3 because Reaction 2 requires more energy than Reaction 3.

• Product B contains more energy at the end of the reaction than reactant A has at the beginning of the reaction.

• Reactant A contains more energy at the beginning of the reaction than product C has at the end of the reaction.

• The data plotted for Reaction 2 and Reaction 3 indicate a difference in the activation energy of these reactions.

Reaction 3 in the graph __________.

• is slower than Reaction 2

• is the same as Reaction 1 but faster

• probably occurred in the presence of an enzyme

• requires more activation energy than Reaction 2