Chemical Reactions Test Review – Physical Science

This flashcard set covers the vocabulary terms, reaction types, indicators, and factors of chemical reactions from the Physical Science test review sheet, including specific chemical formulas and types of reactions.

Chemical reaction

A process where one or more substances are changed into new substances.

Molecular formula

A formula that indicates the actual number of atoms of each element present in a molecule.

Empirical formula

A formula that indicates the simplest whole-number ratio of atoms in a compound.

Subscript

A small number written to the right and below a chemical symbol that indicates the number of atoms of that element in a formula, such as the $2$ in $NO_2$.

Chemical equation

A representation of a chemical reaction using symbols and formulas, such as $H_2 + O_2 \rightarrow H_2O$.

Reactant(s)

The starting substances in a chemical reaction, found on the left side of the reaction arrow.

Product(s)

The substances formed during a chemical reaction, found on the right side of the reaction arrow.

Synthesis reaction

A reaction where two or more substances combine to form a single new compound, such as $2Na + Cl_2 \rightarrow 2NaCl$.

Decomposition reaction

A reaction where a single compound breaks down into two or more simpler substances, such as $2H_2O_2 \rightarrow H_2O + 2O_2$.

Single displacement reaction

A reaction where one element replaces another element in a compound, such as $3AgNO_3 + Al \rightarrow Al(NO_3)_3 + 3Ag$.

Double displacement reaction

A reaction where the positive and negative ions of two ionic compounds exchange places to form two new compounds, such as $Mg(OH)_2 + H_2SO_4 \rightarrow MgSO_4 + 2H_2O$.

Combustion reaction

A chemical reaction where a substance reacts with oxygen ($O_2$), often producing energy in the form of heat and light, such as $C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O$.

Exothermic reaction

A chemical reaction that releases energy to its surroundings, such as paper burning ($C_3H_8$) or a container warming up when an acid is added to a base.

Endothermic reaction

A chemical reaction that absorbs energy from its surroundings, often characterized by a reaction container feeling cold to the touch.

Catalyst

A substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself.

Chemical Reaction Indicators

Five signs that recognize a reaction has occurred: color change, temperature change (energy release/absorption), formation of gas (bubbles), formation of a precipitate (solid), and change in odor.

Factors Affecting Reaction Rate

Five factors including temperature, surface area, concentration, presence of a catalyst, and agitation.

Coefficient

The whole number placed in front of a chemical formula in a balanced equation to satisfy the Law of Conservation of Mass.

Law of Conservation of Mass

The principle that mass is neither created nor destroyed during a chemical reaction, requiring balanced chemical equations to show the same number of atoms on both sides.

Atom Inventory of $Mg_3(PO_4)_2$

Magnesium: $3$; Phosphorus: $2$; Oxygen: $8$.

Atom Inventory of $Ba(NO_3)_2$

Barium: $1$; Nitrogen: $2$; Oxygen: $6$.

Molar Mass

The mass of one mole of a substance, such as Carbon ($C$), Water ($H_2O$), or Sulfur dioxide ($SiO_2$).