Types of Chemical Reactions (College Board AP® Chemistry): Flashcards
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Define acid-base reaction.
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Cards in this collection (34)
Define acid-base reaction.
A reaction involving the transfer of one or more protons between chemical species, where the acid donates protons and the base accepts them.
True or False?
A monoprotic acid can donate two protons in a reaction.
False.
A monoprotic acid donates only one proton. An acid that donates two protons is a diprotic acid (e.g., H2SO4).
In the neutralization reaction between an acid and a base, the products are .......... and .......... .
In the neutralization reaction between an acid and a base, the products are salt and water.
In a neutralization reaction, which ions form the salt product?
The salt is formed from the cation of the base and the anion of the acid. These ions are spectator ions that combine to produce the salt.
True or False?
When an acid reacts with a metal carbonate, one of the products is carbon dioxide gas.
True.
The reaction of an acid with a metal carbonate produces a salt, water, and carbon dioxide (CO2) as a gas.
What salt is produced when hydrochloric acid undergoes neutralization with a base?
A chloride salt is produced. The anion from hydrochloric acid (Cl-) combines with the cation from the base to form the salt.
Define triprotic acid.
An acid that is capable of donating three protons per molecule in a reaction. Example: phosphoric acid (H3PO4).
Define redox reaction.
A reaction involving the transfer of electrons from one reactant to another; oxidation (loss of electrons) and reduction (gain of electrons) occur simultaneously.
In a redox reaction, the species that loses electrons is .......... and the species that gains electrons is .......... .
In a redox reaction, the species that loses electrons is oxidized and the species that gains electrons is reduced.
True or False?
In a redox reaction, electrons lost by one reactant must equal electrons gained by another reactant.
True.
Electron transfer is balanced: every electron lost in the oxidation half-reaction is gained in the reduction half-reaction.
Define combustion reaction.
A redox reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat.
What are the products of the complete combustion of a hydrocarbon?
Complete combustion of a hydrocarbon produces carbon dioxide (CO2) and water (H2O). Complete combustion requires excess oxygen.
True or False?
If all chemical species appear with identical charges on both sides of a full ionic equation, the reaction is a redox reaction.
False.
If all species appear with the same charges on both sides, no electron transfer has occurred and the reaction is not a redox reaction.
Why is the corrosion of a metal classified as an oxidation reaction?
Corrosion involves a metal losing electrons (gaining a positive charge) as it reacts with oxygen or moisture, which defines oxidation. The metal atoms are oxidized from their elemental form to a positive ion.
Define oxidation number.
The hypothetical charge an atom would carry if shared electrons in each bond were assigned entirely to the more electronegative atom. Used to track electron transfer in redox reactions. Also called the oxidation number.
True or False?
The oxidation number of a free element (e.g., Cu or Cl2) is always zero.
True.
Both monatomic free elements (e.g., Cu) and diatomic elements in their elemental form (e.g., Cl2) are assigned an oxidation number of 0.
The sum of oxidation numbers for all atoms in a neutral compound must equal .......... , while for a polyatomic ion it must equal .......... .
The sum of oxidation numbers for all atoms in a neutral compound must equal zero, while for a polyatomic ion it must equal the charge of the ion.
What is the oxidation number of sulfur in SO42-?
The oxidation number of sulfur in SO42- is +6.
Each oxygen is −2; the four oxygen atoms sum to −8. The ion charge is −2, so: S + (−8) = −2, giving S = +6.
True or False?
Group 1 metals always have an oxidation number of +1 in compounds.
True.
Group 1 metals (e.g., Na, K, Li) always carry a +1 oxidation number in compounds, as they lose one electron to form stable ions.
What is the negative oxidation number assigned to elements in Group 17, and why?
Group 17 elements are typically assigned an oxidation number of −1 in compounds, as they need one more electron to achieve a full octet. However, this applies unconditionally only to fluorine (always −1); other halogens (Cl, Br, I) can carry positive oxidation numbers when bonded to a more electronegative atom (e.g., Cl in ClF3 is +3).
What is the oxidation number of carbon in CO2?
The oxidation number of carbon in CO2 is +4.
Each oxygen is −2; two oxygen atoms sum to −4. For the neutral molecule: C + (−4) = 0, so C = +4.
Define half reaction.
A representation of either the oxidation or reduction component of a redox reaction in isolation, showing the electrons lost or gained explicitly.
When balancing a redox reaction by the half-reaction method, why must the number of electrons in each half reaction be made equal before adding them?
Because electrons must cancel completely when the half reactions are added together — the electrons lost in the oxidation half reaction must exactly equal the electrons gained in the reduction half reaction, ensuring no free electrons appear in the overall equation.
When balancing a half reaction in acidic solution, oxygen atoms are balanced by adding .......... and hydrogen atoms are balanced by adding .......... .
When balancing a half reaction in acidic solution, oxygen atoms are balanced by adding H2O and hydrogen atoms are balanced by adding H+.
True or False?
In an oxidation half reaction, electrons appear on the right-hand side of the equation.
True.
Oxidation is loss of electrons, so the electrons released by the species being oxidized appear as products on the right-hand side (e.g., Sn2+ → Sn4+ + 2e-).
In the net ionic equation Sn2+ + 2Fe3+ → Sn4+ + 2Fe2+, which species is the oxidizing agent and why?
Fe3+ is the oxidizing agent because it gains electrons (is reduced from +3 to +2), causing the oxidation of Sn2+. The oxidizing agent is itself reduced in the reaction.
True or False?
The first step when balancing a half reaction is to balance the hydrogen and oxygen atoms.
False.
The first step is to balance elements other than H and O. Oxygen is balanced second (using H2O), hydrogen third (using H+) and charges are balanced last (using e-).
Define precipitation reaction.
A reaction in which two aqueous solutions are mixed and an insoluble solid (the precipitate) forms as a product.
True or False?
All sodium, potassium, ammonium and nitrate salts are soluble in water.
True.
These salts are universally soluble — they do not form precipitates in aqueous solution.
In a precipitation reaction, the ions that do not form the precipitate and remain in solution are called .......... .
In a precipitation reaction, the ions that do not form the precipitate and remain in solution are called spectator ions.
When AgNO3 (aq) and NaCl (aq) are mixed, what precipitate forms and why?
AgCl (s) forms as the precipitate. Although most chlorides are soluble, silver chloride is an exception to the solubility rules — AgCl is insoluble in water.
True or False?
Precipitation reactions are a type of double replacement reaction.
True.
In a precipitation reaction, the cations and anions of two reactants exchange partners to form two new compounds, one of which is insoluble.
Why is it necessary to include a net ionic equation when describing a precipitation reaction?
The net ionic equation removes spectator ions and shows only the species that actually participate in forming the precipitate. It clarifies the essential chemistry: which ions combine to produce the insoluble solid.
Are barium sulfate and calcium sulfate soluble or insoluble in water?
Both barium sulfate (BaSO4) and calcium sulfate (CaSO4) are insoluble in water. They are exceptions to the general rule that sulfates are soluble.
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