Mole Ratio and Stoichiometry Exam Review

Dr. David Block reviews a practice unit exam covering mole ratios, stoichiometry, and types of chemical reactions. The video explains balancing chemical equations, applying the law of conservation of mass, identifying chemical and physical changes, understanding single replacement reactions, and writing chemical formulas. The video aims to clarify common misunderstandings and prepare students for their unit exam.

What is the primary focus of the unit exam?

• Types of chemical reactions

• Balancing equations

• Mole ratios and stoichiometry

• All of the above

What is the ratio of moles of hydrogen consumed to moles of ammonia produced?

• 2:3

• 3:2

• 1:3

• 1:1

How are the atoms in the reactants and products related in a balanced chemical equation?

• Only the type of atoms changes

• They differ in number

• They are identical in number

• None of the above

How much calcium oxide reacts with 88 grams of carbon dioxide?

• 112 grams

• 88 grams

• 200 grams

• None of the above

What principle is applied when calculating the mass of reactants and products?

• Avogadro's law

• Law of multiple proportions

• Law of definite proportions

• Law of conservation of mass

What type of change occurs when atoms rearrange to become a new substance?

• Both A and B

• Chemical change

• Physical change

• None of the above

What reaction type is demonstrated when magnesium combines with hydrochloric acid?

• Double replacement

• Single replacement

• Decomposition

• Synthesis

What is the result of a chemical change?

• Change in temperature

• All of the above

• Formation of a new substance

• Change in state

Which set of products completes and balances the equation for dinitrogen pentoxide gas?

• Option 1

• Option 3

• Option 4

• Option 2

What is the formula for chromium(III) oxide?

• Cr3O2

• CrO3

• Cr2O3

• CrO