year 9 chem

Hydrogen Gas

H2 (G)

Oxygen Gas

O2 (G)

Nitrogen Gas

N2 (G)

Carbon Dioxide Gas

CO2 (G)

Sodium Chloride Salt

NaCl (S)

Sodium Chloride Solution

NaCl (Aq)

Sulfur Dioxide Gas

SO2 (G)

Carbon Monoxide Gas

CO (G)

Methane Gas

CH4 (G)

Solid Sodium Hydroxide

NaOH (S)

Sodium Hydroxide Solution

NaOH (Aq)

atom

Particle that is the basic unit of matter, consisting of protons, neutrons, and electrons. It is the building block of all elements and cannot be broken down further by chemical means. (Hydrogen, H)

ion

Ions are charged atoms or molecules due to electron loss or gain. They are important in chemical reactions.

cation

Cations are positively charged ions

anion

anions are negatively charged ions.

ionic bonding

A chemical bond forms when one atom transfers all its valence electrons to another atom, creating positively charged cations and negatively charged anions.

metallic bonding

Metals bond by delocalising (giving away) their outer shell electrons to become positive cations surrounded by a sea of negative electrons.

when are ions formed?

Ions are formed when an atom gains or loses electrons from the outermost energy shell.

what is a metalloid?

A metalloid is an element with properties of both metals and nonmetals. It shows conductivity like metals, but also has brittleness and poor conductivity like nonmetals. Metalloids are located in the periodic table between metals and nonmetals.

valence electron

The electrons in the outermost energy level of an atom, responsible for bonding and determining the chemical properties of an element.

molecule

Two or more atoms that are chemically bonded. Molecules can be of the same element or a combination of different elements (hydrogen gas, H_²)

compound

Chemical combinations of two or more elements combined in a fixed way. (water H₂O, Salt NaCl)

mixture

Combination of two or more elemonts or compounds which are not chemically bonded together. (juice, sauce)

element

A pure substance containing only one type of atom (H, O, Na)

isotope

An isotope is a variant of an element with the same number of protons but a different number of neutrons in its nucleus. This can make an atom unstable.

chemical reaction

In a chemical reaction, chemical bonds within substances are broken, atoms are rearranged and new bonds are formed to create new molecules/compounds.

What are plastics composed of and what types of plastics exist?

Plastics are composed of long chains of monomers which form in a chemical reaction which are called polymers. Some types of plastics include: polypropylene (PP), polyvinyl chloride (PVC), polystyrene etc. Each type of plastic has its own properties and uses. Plastics are synthetic polymers.

What are the factors that affect a chemical reaction

There are several factors that can affect a chemical reaction:

1. concentration of reactants

2. surface area of reactants

3. temperature of reaction

4. use a catalyst in the reaction

collision theory

For a reaction to occur, particles must collide at the correct orientation and with sufficient energy

What is a physical change?

A physical change refers to a process in which the form or appearance of a substance is altered, but its chemical composition remains the same. Examples of physical changes include changes in state, changes in shape or size, and changes in colour or texture.

nuclear reaction

Nuclear reactions involve changes in the nucleus of an atom, which is the dense central part containing protons and neutrons. These reactions can result in a change in the number of protons or neutrons in an atom, thus changing the type of atom (element) it is.

What is radioactive decay?

The spontaneous process where unstable atomic nuclei release particles or energy to become more stable. It occurs in radioactive substances, causing them to decay over time.

What is alpha radiation?

Alpha - a type of radioactive decay which is released in the form of alpha particles which are very high in energy. The alpha particles consist of two protons and two neutrons bonded together.

beta radiation

Beta radiation is made up of a single positive or negative particle

Gamma radiation

Gamma radiation is electromagnetic radiation with no mass or charge.

What is the worded equation for photosynthesis?

Carbon dioxide + water → glucose + oxygen

What is the worded equation for cellular respiration?

Glucose + oxygen → water + carbon dioxide + energy

Thermosetting plastics

The polymers in thermosetting plastics are joined by strong cross-links. Both high temperatures and strong chemicals are required to break these down. Chemical recycling

Thermosoftening plastics

The polymers in thermosoftening plastics are held together by weak intermolecular forces. Heating breaks these forces which allows plastic to be remoulded. Mechanical recycling

What joins plastics?

Cross-links are chemical bonds which join two polymer chains. When these are added, chains are prevented from sliding over one another, making plastics strong and rigid.