Chemistry Review

What two subatomic particles added together will determine an atoms mass?

• Protons and Electrons
• Electrons and Neutron
• Neutrons and Protons
• Positive and Negative

C₂H₃O₂ How many atoms of oxygen are in two molecules of acetate?

• 2
• 14
• 4
• 10

Which of the following occurrences indicates that a chemical reaction has taken place?

• An odor is produced by burning a sugar cube.
• A puddle is produced by melting an ice cube.
• A loud noise is produced by crushing a can.
• A shard of glass is produced by breaking a bottle.

C₂H₃O₂ How many atoms of carbon are in one molecule of acetate?

• 1
• 2
• 3
• 7

Solid magnesium, Mg, reacts with oxygen gas, O₂, to form the solid magnesium oxide, MgO. Which equation is a balanced chemical equation for this chemical change? 

• 2Mg + O₂ → 2MgO
• Mg + 2O → 2MgO
• Mg + O₂ → MgO₂
• Mg + O → MgO

Glucose (C₆H₁₂O₆) is a kind of sugar molecule. How many atoms are in a molecule of glucose?

• 6
• 12
• 18
• 24

3NaOH + H₃PO₄ → Na₃PO₄ + 3H₂O
Based on these equations, which statement is true? 

• MgO is a reactant in the chemical reactions.
• H₃PO₄ shows that three atoms of oxygen are involved in the reaction.
• O₂ is a catalyst.
• Na₃PO₄ is a product in one of the chemical reactions.

A student observed a precipitate form during a chemical reaction. Which of the following did the student most likely observe? 

• Bubbles of gas floated to the top of a solution.
• A solid sank to the bottom of a container when two liquids were mixed.
• Steam rose from a flask when a powder was added to a liquid.
• The color of a liquid changed when a solid was added to it.

3C₂H₄
How many atoms of carbon are represented by this formula? 

• 2
• 3
• 5
• 6

Fluorine has 7 valence electrons. How many more electrons does it need to achieve a full outermost energy level?

• 1
• 3
• 7
• 10