Physical Science: Chemical Reactions and Balancing Equations

Comprehensive practice vocabulary flashcards covering chemical reaction types, evidence of chemical change, reaction rates, collision theory, Le Châtelier's principle, equilibrium, and 51 balanced chemical equations.

Chemical Change Evidence: Distinct Smell

The production of an unexpected or characteristic odor that indicates a chemical reaction has taken place.

Chemical Change Evidence: Color Change

An alteration in color resulting from the formation of a new chemical substance.

Chemical Change Evidence: Temperature Change

A release or absorption of thermal energy occurring as chemical bonds are broken and formed.

Chemical Change Evidence: Precipitate Formation

The appearance of an insoluble solid that falls out of a liquid solution during a reaction.

Chemical Change Evidence: Bubble Formation

The generation and release of gas particles during a chemical reaction in a liquid.

Change in Size

A physical change in dimensions that does not indicate a chemical reaction has occurred.

Formation of a New Substance

The definitive criterion that guarantees a chemical reaction has taken place, distinguishing it from physical changes.

Boiling Water

A physical change in state from a liquid to a gas that is not a chemical reaction.

Reactants

The initial substances that undergo change during a chemical reaction.

Products

Substances that are produced as a result of a chemical reaction.

Balanced Chemical Equation

A chemical equation with equal numbers of atoms of each element on both sides of the arrow, demonstrating conservation of mass.

Unbalanced Chemical Equation

A chemical equation where the number of atoms of each element is not equal on both sides, such as $2\text{Al} + 3\text{O}_2 \rightarrow \text{Al}_2\text{O}_3$.

Combustion of Magnesium

The reaction of magnesium metal burning in gaseous oxygen, represented by the balanced equation $2\text{Mg} + \text{O}_2 \rightarrow 2\text{MgO}$.

Mole

A fundamental chemical quantity used to count atoms, molecules, or formula units.

Ammonia Synthesis Mole Ratio

The reaction $\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$, which produces exactly $2$ moles of ammonia ($\text{NH}_3$).

Decomposition Reaction

A chemical reaction where a single reactant breaks down into two or more products.

Single-Replacement Reaction

A chemical reaction where both reactants and products include an element and a compound.

Double-Replacement Reaction

A chemical reaction in which two compounds swap ions to form two new compounds.

Synthesis Reaction

A chemical reaction in which two or more reactants combine to form a single product.

Reversible Reaction

A chemical reaction where products can react to reform reactants, proceeding simultaneously in forward and reverse directions.

Oxidation

Any chemical process in which an element or compound loses electrons.

Reduction

Any chemical process in which an element or compound gains electrons.

Redox Reaction

An oxidation-reduction reaction in which elements gain or lose electrons.

Combustion Reaction

A chemical reaction that strictly requires oxygen and fuel, releasing heat and light.

Oxygen Requirement in Oxidation vs. Combustion

Combustion strictly requires oxygen, whereas oxidation refers broadly to electron loss and does not require oxygen.

Exothermic Reaction

A chemical reaction that gives off thermal energy to its surroundings.

Endothermic Reaction

A chemical reaction that absorbs energy from its surroundings.

Conservation of Energy in a Campfire

Energy is released as thermal and light energy and absorbed by the environment; no energy is destroyed by combustion.

Collision Model

The framework requiring that reactant particles must collide, have enough energy, and be properly aligned for a reaction to occur.

Collision Alignment

The spatial orientation required between colliding reactant particles to facilitate bond breaking and rearrangement.

Collision Energy Threshold

The minimum kinetic energy that colliding particles must possess to initiate a chemical reaction.

Reaction Rate: Surface Area

Dividing a large reactant into smaller pieces increases the exposed surface area, increasing the frequency of collisions and the reaction rate.

Reaction Rate: Temperature Effect

Lowering temperature decreases particle speed and collision frequency, whereas increasing temperature accelerates the reaction.

Reaction Rate: Concentration Effect

Increasing the concentration of reactants increases particle density, raising collision frequency and speeding up the reaction.

Reaction Rate: Agitation

Stirring increases the contact and collisions between reactant particles, whereas preventing stirring decreases the reaction rate.

Activation Energy

The minimum energy needed to get a chemical reaction started.

Catalyst

A substance that increases the rate of a chemical reaction by lowering its activation energy.

Enzyme

A biological catalyst that increases reaction rates in living organisms.

Inhibitor

A substance that slows the rate of a chemical reaction by reducing the effect of catalysts.

Chemical Equilibrium

A dynamic state in which the forward and reverse reactions continue to occur at the exact same rate.

Equilibrium State Particle Count

In chemical equilibrium, the total number of each type of particle remains constant.

Le Châtelier's Principle

The principle stating that a system in equilibrium will adjust its equilibrium state to reduce the effect of any applied changes.

Equilibrium Stress: Removing Water from $2\text{H}_2\text{O}_2 \rightleftharpoons 2\text{H}_2\text{O} + \text{O}_2$

Removing water causes the equilibrium to shift forward, decomposing more hydrogen peroxide into water and oxygen.

Equilibrium Stress: Pressure on $2\text{H}_2\text{O}_2(l) \rightleftharpoons 2\text{H}_2\text{O}(g) + \text{O}_2(g)$

Increasing pressure causes the system to shift toward synthesizing hydrogen peroxide to reduce the total number of gas particles.

Equilibrium Stress: Temperature Decrease

Decreasing system temperature shifts the chemical equilibrium toward the side of the reaction that releases energy.

Reaction: $\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$

A decomposition reaction in which calcium carbonate breaks down into calcium oxide and carbon dioxide gas.

Reaction: $\text{C}_2\text{N}_2 + 2\text{O}_2 \rightarrow 2\text{CO}_2 + \text{N}_2$

A single-replacement reaction in which cyanogen reacts with oxygen gas.

Reaction: $\text{HCl} + \text{KOH} \rightarrow \text{H}_2\text{O} + \text{KCl}$

A double-replacement acid-base neutralization reaction forming water and potassium chloride.

Reaction: $\text{N}_2 + 2\text{O}_2 \rightarrow 2\text{NO}_2$

A synthesis reaction combining nitrogen and oxygen to produce nitrogen dioxide.

Reaction: $\text{NH}_4\text{Cl} \rightleftharpoons \text{NH}_3 + \text{HCl}$

A reversible reaction involving ammonium chloride decomposing into ammonia and hydrogen chloride and reforming.

Balancing: $\text{Fe} + \text{Cl}_2 \rightarrow \text{FeCl}_3$

The balanced chemical equation is $2\text{Fe} + 3\text{Cl}_2 \rightarrow 2\text{FeCl}_3$.

Balancing: $\text{Fe} + \text{O}_2 \rightarrow \text{Fe}_2\text{O}_3$

The balanced chemical equation is $4\text{Fe} + 3\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3$.

Balancing: $\text{FeBr}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{Fe}_2(\text{SO}_4)_3 + \text{HBr}$

The balanced chemical equation is $2\text{FeBr}_3 + 3\text{H}_2\text{SO}_4 \rightarrow \text{Fe}_2(\text{SO}_4)_3 + 6\text{HBr}$.

Balancing: $\text{C}_4\text{H}_6\text{O}_3 + \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_4\text{O}_2$

The balanced chemical equation is $\text{C}_4\text{H}_6\text{O}_3 + \text{H}_2\text{O} \rightarrow 2\text{C}_2\text{H}_4\text{O}_2$.

Balancing: $\text{C}_2\text{H}_4 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O}$.

Balancing: $\text{C}_4\text{H}_{10}\text{O} + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{C}_4\text{H}_{10}\text{O} + 6\text{O}_2 \rightarrow 4\text{CO}_2 + 5\text{H}_2\text{O}$.

Balancing: $\text{C}_7\text{H}_{16} + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{C}_7\text{H}_{16} + 11\text{O}_2 \rightarrow 7\text{CO}_2 + 8\text{H}_2\text{O}$.

Balancing: $\text{H}_2\text{SiCl}_2 + \text{H}_2\text{O} \rightarrow \text{H}_8\text{Si}_4\text{O}_4 + \text{HCl}$

The balanced chemical equation is $4\text{H}_2\text{SiCl}_2 + 4\text{H}_2\text{O} \rightarrow \text{H}_8\text{Si}_4\text{O}_4 + 8\text{HCl}$.

Balancing: $\text{HSiCl}_3 + \text{H}_2\text{O} \rightarrow \text{H}_{10}\text{Si}_{10}\text{O}_{15} + \text{HCl}$

The balanced chemical equation is $10\text{HSiCl}_3 + 15\text{H}_2\text{O} \rightarrow \text{H}_{10}\text{Si}_{10}\text{O}_{15} + 30\text{HCl}$.

Balancing: $\text{C}_7\text{H}_9 + \text{HNO}_3 \rightarrow \text{C}_7\text{H}_6(\text{NO}_2)_3 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{C}_7\text{H}_9 + 3\text{HNO}_3 \rightarrow \text{C}_7\text{H}_6(\text{NO}_2)_3 + 3\text{H}_2\text{O}$.

Balancing: $\text{C}_5\text{H}_8\text{O}_2 + \text{NaH} + \text{HCl} \rightarrow \text{C}_5\text{H}_{12}\text{O}_2 + \text{NaCl}$

The balanced chemical equation is $\text{C}_5\text{H}_8\text{O}_2 + 2\text{NaH} + 2\text{HCl} \rightarrow \text{C}_5\text{H}_{12}\text{O}_2 + 2\text{NaCl}$.

Balancing: $\text{Fe} + \text{H}_2\text{SO}_4 \rightarrow \text{Fe}_2(\text{SO}_4)_3 + \text{H}_2$

The balanced chemical equation is $2\text{Fe} + 3\text{H}_2\text{SO}_4 \rightarrow \text{Fe}_2(\text{SO}_4)_3 + 3\text{H}_2$.

Balancing: $\text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{H}_2\text{O} + \text{CO}_2$

The balanced chemical equation is $2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 6\text{H}_2\text{O} + 4\text{CO}_2$.

Balancing: $\text{KOH} + \text{H}_3\text{PO}_4 \rightarrow \text{K}_3\text{PO}_4 + \text{H}_2\text{O}$

The balanced chemical equation is $3\text{KOH} + \text{H}_3\text{PO}_4 \rightarrow \text{K}_3\text{PO}_4 + 3\text{H}_2\text{O}$.

Balancing: $\text{SnO}_2 + \text{H}_2 \rightarrow \text{Sn} + \text{H}_2\text{O}$

The balanced chemical equation is SnO2 +2H2

Balancing: $\text{NH}_3 + \text{O}_2 \rightarrow \text{NO} + \text{H}_2\text{O}$

The balanced chemical equation is $4\text{NH}_3 + 5\text{O}_2 \rightarrow 4\text{NO} + 6\text{H}_2\text{O}$.

Balancing: $\text{KNO}_3 + \text{H}_2\text{CO}_3 \rightarrow \text{K}_2\text{CO}_3 + \text{HNO}_3$

The balanced chemical equation is $2\text{KNO}_3 + \text{H}_2\text{CO}_3 \rightarrow \text{K}_2\text{CO}_3 + 2\text{HNO}_3$.

Balancing: $\text{B}_2\text{Br}_6 + \text{HNO}_3 \rightarrow \text{B}(\text{NO}_3)_3 + \text{HBr}$

The balanced chemical equation is $\text{B}_2\text{Br}_6 + 6\text{HNO}_3 \rightarrow 2\text{B}(\text{NO}_3)_3 + 6\text{HBr}$.

Balancing: $\text{BF}_3 + \text{Li}_2\text{SO}_3 \rightarrow \text{B}_2(\text{SO}_3)_3 + \text{LiF}$

The balanced chemical equation is $2\text{BF}_3 + 3\text{Li}_2\text{SO}_3 \rightarrow \text{B}_2(\text{SO}_3)_3 + 6\text{LiF}$.

Balancing: $(\text{NH}_4)_3\text{PO}_4 + \text{Pb}(\text{NO}_3)_4 \rightarrow \text{Pb}_3(\text{PO}_4)_4 + \text{NH}_4\text{NO}_3$

The balanced chemical equation is $4(\text{NH}_4)_3\text{PO}_4 + 3\text{Pb}(\text{NO}_3)_4 \rightarrow \text{Pb}_3(\text{PO}_4)_4 + 12\text{NH}_4\text{NO}_3$.

Balancing: $\text{SeCl}_6 + \text{O}_2 \rightarrow \text{SeO}_2 + \text{Cl}_2$

The balanced chemical equation is $\text{SeCl}_6 + \text{O}_2 \rightarrow \text{SeO}_2 + 3\text{Cl}_2$.

Balancing: $\text{CH}_4 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$.

Balancing: $\text{Na}^+ + \text{Cl}^- \rightarrow \text{NaCl}$

The balanced chemical equation is $\text{Na}^+ + \text{Cl}^- \rightarrow \text{NaCl}$.

Balancing: $\text{Al} + \text{O}_2 \rightarrow \text{Al}_2\text{O}_3$

The balanced chemical equation is $4\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3$.

Balancing: $\text{N}_2 + \text{H}_2 \rightarrow \text{NH}_3$

The balanced chemical equation is $\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$.

Balancing: $\text{CO}(g) + \text{H}_2(g) \rightarrow \text{C}_8\text{H}_{18}(l) + \text{H}_2\text{O}$

The balanced chemical equation is $8\text{CO}(g) + 17\text{H}_2(g) \rightarrow \text{C}_8\text{H}_{18}(l) + 8\text{H}_2\text{O}$.

Balancing: $\text{FeO}_3(s) + \text{CO}(g) \rightarrow \text{Fe}(l) + \text{CO}_2(g)$

The balanced chemical equation is $\text{FeO}_3(s) + 3\text{CO}(g) \rightarrow \text{Fe}(l) + 3\text{CO}_2(g)$.

Balancing: $\text{H}_2\text{SO}_4 + \text{Pb}(\text{OH})_4 \rightarrow \text{Pb}(\text{SO}_4)_2 + \text{H}_2\text{O}$

The balanced chemical equation is $2\text{H}_2\text{SO}_4 + \text{Pb}(\text{OH})_4 \rightarrow \text{Pb}(\text{SO}_4)_2 + 4\text{H}_2\text{O}$.

Balancing: $\text{Al} + \text{HCl} \rightarrow \text{AlCl}_3 + \text{H}_2$

The balanced chemical equation is $2\text{Al} + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2$.

Balancing: $\text{Ca}_3(\text{PO}_4)_2 + \text{H}_2\text{SO}_4 \rightarrow \text{CaSO}_4 + \text{Ca}(\text{H}_2\text{PO}_4)_2$

The balanced chemical equation is $\text{Ca}_3(\text{PO}_4)_2 + 2\text{H}_2\text{SO}_4 \rightarrow 2\text{CaSO}_4 + \text{Ca}(\text{H}_2\text{PO}_4)_2$.

Balancing: $\text{H}_3\text{PO}_4 + \text{HCl} \rightarrow \text{PCl}_5 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{H}_3\text{PO}_4 + 5\text{HCl} \rightarrow \text{PCl}_5 + 4\text{H}_2\text{O}$.

Balancing: $\text{SiCl}_4(l) + \text{H}_2\text{O}(l) \rightarrow \text{SiO}_2(s) + \text{HCl}(aq)$

The balanced chemical equation is $\text{SiCl}_4(l) + 2\text{H}_2\text{O}(l) \rightarrow \text{SiO}_2(s) + 4\text{HCl}(aq)$.

Balancing: $\text{As} + \text{NaOH} \rightarrow \text{Na}_3\text{AsO}_3 + \text{H}_2$

The balanced chemical equation is $2\text{As} + 6\text{NaOH} \rightarrow 2\text{Na}_3\text{AsO}_3 + 3\text{H}_2$.

Balancing: $\text{Au}_2\text{S}_3 + \text{H}_2 \rightarrow \text{Au} + \text{H}_2\text{S}$

The balanced chemical equation is $\text{Au}_2\text{S}_3 + 3\text{H}_2 \rightarrow 2\text{Au} + 3\text{H}_2\text{S}$.

Balancing: $\text{V}_2\text{O}_5 + \text{HCl} \rightarrow \text{VOCl}_3 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{V}_2\text{O}_5 + 6\text{HCl} \rightarrow 2\text{VOCl}_3 + 3\text{H}_2\text{O}$.

Balancing: $\text{Hg}(\text{OH})_2 + \text{H}_3\text{PO}_4 \rightarrow \text{Hg}_3(\text{PO}_4)_2 + \text{H}_2\text{O}$

The balanced chemical equation is $3\text{Hg}(\text{OH})_2 + 2\text{H}_3\text{PO}_4 \rightarrow \text{Hg}_3(\text{PO}_4)_2 + 6\text{H}_2\text{O}$.

Balancing: $\text{SiO}_2 + \text{HF} \rightarrow \text{SiF}_4 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{SiO}_2 + 4\text{HF} \rightarrow \text{SiF}_4 + 2\text{H}_2\text{O}$.

Balancing: $\text{Zn} + \text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2$

The balanced chemical equation is $\text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2$.

Balancing: $\text{HClO}_4 + \text{P}_4\text{O}_{10} \rightarrow \text{H}_3\text{PO}_4 + \text{Cl}_2\text{O}_7$

The balanced chemical equation is $12\text{HClO}_4 + \text{P}_4\text{O}_{10} \rightarrow 4\text{H}_3\text{PO}_4 + 6\text{Cl}_2\text{O}_7$.

Balancing: $\text{N}_2(g) + \text{O}_2(g) + \text{H}_2\text{O} \rightarrow \text{HNO}_3(aq)$

The balanced chemical equation is $2\text{N}_2(g) + 5\text{O}_2(g) + 2\text{H}_2\text{O} \rightarrow 4\text{HNO}_3(aq)$.

Balancing: $\text{NH}_4\text{NO}_3 \rightarrow \text{N}_2 + \text{O}_2 + \text{H}_2\text{O}$

The balanced chemical equation is $2\text{NH}_4\text{NO}_3 \rightarrow 2\text{N}_2 + \text{O}_2 + 4\text{H}_2\text{O}$.

Balancing: $\text{AgI} + \text{Na}_2\text{S} \rightarrow \text{Ag}_2\text{S} + \text{NaI}$

The balanced chemical equation is $2\text{AgI} + \text{Na}_2\text{S} \rightarrow \text{Ag}_2\text{S} + 2\text{NaI}$.

Balancing: $\text{Na}_3\text{PO}_4 + \text{HCl} \rightarrow \text{NaCl} + \text{H}_3\text{PO}_4$

The balanced chemical equation is $\text{Na}_3\text{PO}_4 + 3\text{HCl} \rightarrow 3\text{NaCl} + \text{H}_3\text{PO}_4$.

Balancing: $\text{Ba}_3\text{N}_2 + \text{H}_2\text{O} \rightarrow \text{Ba}(\text{OH})_2 + \text{NH}_3$

The balanced chemical equation is $\text{Ba}_3\text{N}_2 + 6\text{H}_2\text{O} \rightarrow 3\text{Ba}(\text{OH})_2 + 2\text{NH}_3$.

Balancing: $\text{TiCl}_4 + \text{H}_2\text{O} \rightarrow \text{TiO}_2 + \text{HCl}$

The balanced chemical equation is $\text{TiCl}_4 + 2\text{H}_2\text{O} \rightarrow \text{TiO}_2 + 4\text{HCl}$.

Balancing: $\text{CaCl}_2 + \text{Na}_3\text{PO}_4 \rightarrow \text{Ca}_3(\text{PO}_4)_2 + \text{NaCl}$

The balanced chemical equation is $3\text{CaCl}_2 + 2\text{Na}_3\text{PO}_4 \rightarrow \text{Ca}_3(\text{PO}_4)_2 + 6\text{NaCl}$.

Balancing: $\text{NaBr} + \text{Cl}_2 \rightarrow \text{NaCl} + \text{Br}_2$

The balanced chemical equation is $2\text{NaBr} + \text{Cl}_2 \rightarrow 2\text{NaCl} + \text{Br}_2$.

Balancing: $\text{Mg}(\text{OH})_2 + \text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2\text{O}$

The balanced chemical equation is $\text{Mg}(\text{OH})_2 + 2\text{HCl} \rightarrow \text{MgCl}_2 + 2\text{H}_2\text{O}$.

Balancing: $\text{FeS} + \text{O}_2 \rightarrow \text{Fe}_2\text{O}_3 + \text{SO}_2$

The balanced chemical equation is $4\text{FeS} + 7\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 4\text{SO}_2$.

Balancing: $\text{PCl}_5 + \text{H}_2\text{O} \rightarrow \text{H}_3\text{PO}_4 + \text{HCl}$

The balanced chemical equation is $\text{PCl}_5 + 4\text{H}_2\text{O} \rightarrow \text{H}_3\text{PO}_4 + 5\text{HCl}$.