Final Exam Study Guide

What is a chemical reaction?

A process where reactants break and form chemical bonds to create new substances called products.

What are reactants?

The starting substances in a chemical reaction.

What are products?

The new substances formed in a chemical reaction.

What does the Law of Conservation of Mass state?

Matter cannot be created or destroyed during a chemical reaction.

Why must equations be balanced?

Because the number of atoms must be equal on both sides of the equation.

What do coefficients do in equations?

They balance the number of atoms.

What should NEVER be changed when balancing equations?

Subscripts.

What does (s) mean?

Solid.

What does (l) mean?

Liquid.

What does (g) mean?

Gas.

What does (aq) mean?

Aqueous, dissolved in water.

What is a single replacement reaction?

A reaction where one element replaces another in a compound.

General form of a single replacement reaction?

A + BC → AC + B.

What determines whether a single replacement reaction occurs?

The activity series.

What is the activity series?

A list ranking metals by reactivity.

Rule for the activity series?

A more reactive metal replaces a less reactive metal.

What happens if the metal is less reactive?

No reaction (NR).

Why do gold and silver rarely react?

They are very unreactive metals.

What gas commonly forms when metals react with acids?

Hydrogen gas (H₂).

Why does hydrogen gas form in metal

acid reactions?

Example of a metal

acid reaction?

What is a double replacement reaction?

A reaction where two compounds exchange ions.

General form of a double replacement reaction?

AB + CD → AD + CB.

What are the two main types of double replacement reactions?

Precipitation and neutralization.

What is a neutralization reaction?

A reaction between an acid and a base that forms water and a salt.

General form of neutralization?

Acid + Base → Salt + H₂O.

Why is water formed in neutralization reactions?

H⁺ ions combine with OH⁻ ions.

Net ionic equation for neutralization?

H⁺ + OH⁻ → H₂O.

What is a precipitation reaction?

A reaction that forms an insoluble solid called a precipitate.

What is a precipitate?

An insoluble solid formed in a reaction.

Example of a precipitation reaction?

AgNO₃ + NaCl → AgCl(s) + NaNO₃(aq).

Which compounds are always soluble?

Group 1 compounds, nitrates, and ammonium compounds.

Are nitrates soluble or insoluble?

Soluble.

Are Group 1 compounds soluble or insoluble?

Soluble.

Are most carbonates soluble or insoluble?

Insoluble.

Is AgCl soluble or insoluble?

Insoluble.

Is BaSO₄ soluble or insoluble?

Insoluble.

What is a complete ionic equation?

An equation showing all aqueous compounds split into ions.

What is a net ionic equation?

An equation showing only the ions that participate in the reaction.

What is a spectator ion?

An ion that does not participate in the reaction.

Why write complete ionic equations first?

To identify spectator ions.

What stays together in ionic equations?

Solids, liquids, and gases.

What splits apart in ionic equations?

Aqueous ionic compounds.

Net ionic equation for AgNO₃ + NaCl?

Ag⁺ + Cl⁻ → AgCl(s).

Spectator ions in AgNO₃ + NaCl?

Na⁺ and NO₃⁻.

How do you identify a single replacement reaction?

One element replaces another element.

How do you identify a double replacement reaction?

Two compounds exchange ions.

How do you identify a neutralization reaction?

Acid + base → water + salt.

How do you identify a precipitation reaction?

An insoluble solid forms.

How do you identify gas formation?

Gas bubbles form, usually H₂ or CO₂.

What happens when acids react with metal carbonates?

They produce a salt, water, and carbon dioxide gas.

Example of acid + carbonate reaction?

2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂.

First step in balancing equations?

Write correct formulas.

Second step in balancing equations?

Count atoms on both sides.

Third step in balancing equations?

Add coefficients to balance atoms.

Final step in balancing equations?

Recheck atoms and charges.

Why are ion charges important?

They determine compound formulas.

Charge of sodium ion?

Na⁺.

Charge of chloride ion?

Cl⁻.

Charge of calcium ion?

Ca²⁺.

Formula formed by Ca²⁺ and Cl⁻?

CaCl₂.

Metal + acid → ?

Salt + hydrogen gas.

Acid + base → ?

Salt + water.

Acid + carbonate → ?

Salt + water + CO₂.

Double replacement reactions usually occur between what type of compounds?

Ionic compounds in aqueous solution.

Zn + CuSO₄ → ?

ZnSO₄ + Cu.

Ag + HCl → ?

NR.

Ca + H₂O → ?

Ca(OH)₂ + H₂.

HCl + NaOH → ?

NaCl + H₂O.

AgNO₃ + NaCl → ?

AgCl + NaNO₃.

What does aqueous mean?

Dissolved in water.

Which ions are always aqueous?

Group 1 ions and ammonium (NH₄⁺).

Are all nitrates aqueous?

Yes, all nitrates are soluble in water.

Are acetates usually aqueous?

Yes.

Are chlorides usually aqueous?

Yes, except AgCl, PbCl₂, and Hg₂Cl₂.

Are sulfates usually aqueous?

Yes, except BaSO₄, PbSO₄, and CaSO₄.

Are carbonates usually aqueous?

No, most are insoluble except Group 1 and NH₄⁺ carbonates.

Are hydroxides usually aqueous?

No, most are insoluble except Group 1 and slightly Ca(OH)₂ and Ba(OH)₂.

How do you know if a precipitate forms?

If one product is insoluble according to solubility rules.

What state is a precipitate written as?

Solid (s).

What state are soluble ionic compounds written as?

Aqueous (aq).

What happens to aqueous ionic compounds in ionic equations?

They split into ions.

Do solids split into ions in ionic equations?

No.

Do liquids split into ions in ionic equations?

No.

Do gases split into ions in ionic equations?

No.

What are the most important solubility rules to memorize?

Group 1, NH₄⁺, and NO₃⁻ are always soluble

AgCl, BaSO₄, PbI₂, and most carbonates are insoluble.