Chemical Reactions & Equations

What are the five main types of chemical reactions?

• Addition, subtraction, multiplication, division, and exponentiation

• Synthesis, decomposition, single displacement, double displacement, and combustion

Explain the difference between a synthesis reaction and a decomposition reaction.

• Synthesis reactions occur spontaneously, while decomposition reactions require a catalyst.

• Synthesis reactions break down compounds, while decomposition reactions combine substances.

• Synthesis reactions involve the release of energy, while decomposition reactions absorb energy.

• The main difference is that synthesis reactions combine substances, while decomposition reactions break down compounds.

Tags

NGSS.MS-PS1-5

Why is it important to balance chemical equations?

• To waste time and resources

• To create confusion in the scientific community

• To make the equations look more complicated

• To ensure the law of conservation of mass is obeyed.

Tags

NGSS.HS-PS1-7

Balance the following chemical equation: H2 + O2 -> H2O

• H2O -> H2 + O2

• H2O2 -> H2 + O2

• H2 + O2 -> H2O2

• H2 + O2 -> 2H2O

Tags

NGSS.MS-PS1-5

In a combustion reaction, what are the typical products formed?

• Oxygen and nitrogen

• Hydrogen and helium

• Carbon dioxide and water

• Carbon monoxide and sulfur dioxide

What is the law of conservation of mass and how does it relate to balancing chemical equations?

• The law of conservation of mass is not applicable to chemical reactions

• Balancing chemical equations ensures that the number of atoms changes on both sides of the equation

• The law of conservation of mass states that mass is created in a chemical reaction

• The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction, it is only rearranged. Balancing chemical equations ensures that the same number of each type of atom is present on both sides of the equation, thus following the law of conservation of mass.

Tags

NGSS.HS-PS1-7

What is a double displacement reaction? Provide an example.

• A double displacement reaction involves the exchange of electrons between two reactants

• In a double displacement reaction, the products have the same chemical formula as the reactants

• An example of a double displacement reaction is the reaction between hydrochloric acid and sodium hydroxide

• An example of a double displacement reaction is the reaction between silver nitrate (AgNO3) and sodium chloride (NaCl) to form silver chloride (AgCl) and sodium nitrate (NaNO3).

Balance the following chemical equation: Fe + O2 -> Fe2O3

• 4Fe + 3O2 -> 2Fe2O3

• Fe2 + O2 -> Fe2O3

• 2Fe + 3O2 -> Fe2O3

• Fe + O2 -> Fe3O2

Tags

NGSS.HS-PS1-7

Why do chemical reactions need to be classified into different types?

• To help understand and predict how substances will interact with each other, to identify reaction patterns, and to facilitate communication among scientists.

• To prevent advancements in chemical research

• To create unnecessary complexity in the field of chemistry

• To confuse scientists and make it harder to understand reactions

Tags

NGSS.HS-PS1-1

What is the difference between an exothermic and endothermic reaction?

• An exothermic reaction absorbs heat, while an endothermic reaction releases heat.

• An exothermic reaction releases heat, while an endothermic reaction absorbs heat.

• An exothermic reaction involves the formation of new compounds, while an endothermic reaction involves the breakdown of compounds.

• An exothermic reaction is always spontaneous, while an endothermic reaction requires a catalyst.

Tags

NGSS.HS-PS1-4