Chemical Changes Supplementary Notes

This set of vocabulary flashcards covers the fundamental concepts of chemical changes, naming conventions for compounds, properties of acids and alkalis, and common chemical tests as detailed in the lecture notes.

Chemical change

A change that involves the formation of new substance(s) and is difficult to reverse.

Physical change

A change that does not produce new substance(s), can be easily reversed, and does not involve the production or absorption of heat and/or light energy.

Reactants

Substances that react or undergo a reaction, written on the left side of a chemical equation.

Products

Substances that are produced in a reaction, written on the right side of a chemical equation.

Word equation

A way to represent a chemical change where the names of the reactants and products are written out in words.

Conservation of mass

A principle stating that the total mass of the reactants is equal to the total mass of the products in a chemical reaction.

Balanced chemical equation

An equation where the number of the different types of atoms before and after the reaction are equal.

Diatomic gases

Gases like hydrogen, oxygen, chlorine, nitrogen, and fluorine that consist of molecules made from 2 atoms of the same element.

Binary compound naming (metal and non-metal)

The name usually follows the form metal-non-metal, where the metal retains its name and the non-metal changes its ending to "-ide."

Prefixes (mono-, di-, tri-, tetra-)

Used in naming compounds made from non-metal elements to indicate the number of atoms: "mono-" means one, "di-" means two, "tri-" means three, and "tetra-" means four.

Water

A compound with the special chemical symbol $H_{2}O$.

Ammonia

A compound with the special chemical symbol $NH_{3}$.

Methane

A compound with the special chemical symbol $CH_{4}$.

Roman numerals

Numbers attached to metal names in compounds to indicate their charge or oxidation state, such as iron (II) or iron (III).

Polyatomic ions

Ions carry negative charges and are made from a combination of non-metals, such as Nitrate, Carbonate, and Sulfate ions.

Acid

A chemical that, when dissolved in water, will ionise to produce hydrogen ions ($H^{+}$) as the only positive ions.

Hydrochloric acid

A lab acid with the chemical symbol $HCl_{(aq)}$.

Nitric acid

A lab acid with the chemical symbol $HNO_{3(aq)}$.

Sulfuric acid

A lab acid with the chemical symbol $H_{2}SO_{4(aq)}$.

Base

A substance that is usually a metal oxide or a metal hydroxide, such as sodium hydroxide ($NaOH$) or copper (II) oxide ($CuO$).

Alkali

A base which is soluble in water and produces hydroxide ions ($OH^{-}$) as the only negative ions.

Neutralisation

A chemical reaction between an acid and a base (or alkali) that produces salt and water only.

Indicator

A chemical that changes colour depending on the acidity of the solution.

pH scale

A scale from $0$ to $14$ used to show the degree of acidity; values smaller than $7$ are acidic, $7$ is neutral, and values larger than $7$ are alkaline.

Universal Indicator

An indicator that gives a range of colors: red to yellow for acidic, green for neutral, and blue to purple for alkaline.

Acid and metal reaction

A reaction that produces a salt and hydrogen gas: $\text{acid} + \text{metal} \rightarrow \text{salt} + \text{hydrogen gas}$.

Acid and carbonate reaction

A reaction that produces a salt, carbon dioxide gas, and water: $\text{acid} + \text{carbonate} \rightarrow \text{salt} + \text{carbon dioxide} + \text{water}$.

Hydrogen gas test

A test involving a burning or lighted splint, which will be extinguished with a 'pop' sound if the gas is present.

Carbon dioxide gas test

A test where the gas is passed into limewater; if present, a white precipitate (calcium carbonate) is formed.