Year 9 Science - Chemical Sciences Revision

These flashcards cover key concepts in chemical sciences for Year 9 science students, including atomic structure, chemical reactions, and properties of acids and bases.

What is matter composed of?

All matter is made of atoms, which are composed of protons, neutrons, and electrons.

What is natural radioactivity?

Natural radioactivity arises from the decay of nuclei in atoms.

What happens during a chemical reaction regarding mass?

During a chemical reaction, mass is not created or destroyed.

Where can protons and neutrons be found in an atom?

Protons and neutrons are found in the nucleus of an atom.

What is the charge of protons and electrons?

Protons have a positive charge while electrons have a negative charge.

What do you call atoms with the same number of protons but different numbers of neutrons?

These are called isotopes.

What formula represents combustion?

Combustion occurs when a substance reacts with oxygen gas, producing heat, light, and often carbon dioxide and water.

What are ionic compounds made of?

Ionic compounds are made up of metals and non-metals.

How does a base generally react in water?

A base generally forms hydroxide (OH-) or oxide (O) ions in water.

What is the difference between concentrated and diluted acids?

Concentrated acids have little or no water added, while diluted acids contain a large amount of water.

What are the properties of acids?

Acids produce hydrogen ions (H+) when dissolved in water and often taste sour.

What is an exothermic reaction?

An exothermic reaction is a chemical reaction that releases heat.

What is an endothermic reaction?

An endothermic reaction is a chemical reaction that absorbs heat.

What does the pH scale measure?

The pH scale measures the acidity or basicity of a solution.

What is the primary product formed when an acid reacts with a metal carbonate?

The primary products are a salt, carbon dioxide, and water.

Who is credited with the discovery of the electron?

J.J. Thomson is credited with the discovery of the electron.

What is the name of the model proposed by Rutherford?

The Rutherford model describes the atom as having a dense positive nucleus surrounded by electrons.

What is meant by the Law of Conservation of Mass?

The Law of Conservation of Mass states that mass cannot be created or destroyed in a chemical reaction.

What happens to the pH of an acid when it is diluted with water?

The pH of an acid increases (becomes less acidic) when it is diluted with water.