7H Atoms, Elements & Molecules

Flashcards about chemical reactions, the periodic table, and data representation.

What is a bar chart?

A chart where the lengths or heights of bars (rectangles) represent the values of the variables.

What is continuous data?

Data values that can change gradually and can have any value (between two limits) are continuous (e.g. human height).

What is data?

Observations or measurements collected in investigations.

What is discontinuous data?

Data values that can only have one of a set number of options are discontinuous (e.g. shoe sizes and days of the week).

What is discrete data?

Data that involves a limited number of values (numbers).

What is gas?

One of the states of matter. Does not have a fixed shape or a fixed volume and is easy to squash.

What is a line graph?

A graph that shows how one variable changes when another changes (usually time). The points are joined with straight lines.

What is a line of best fit?

A line drawn on a scatter graph that goes through the middle of the points, so that about half the points are above the line and about half of them are below the line.

What is oxygen?

A gas that makes up about 21% of the air.

What is a pie chart?

A type of chart in which a circle is divided into sectors to represent the proportions of a total made up by different items.

What is qualitative data?

Data that is described in words.

What is quantitative data?

Data that is described in numbers.

What is a relationship?

A link between two variables, so that when one thing changes so does the other. Best seen by using a scatter graph. Also called a correlation.

What is a scatter graph?

A graph in which data for two variables is plotted as points. This allows you to see whether there is a relationship between the two variables. Lines (or curves) of best fit are often drawn through the points.

What is a table?

An organisation of data into rows and columns.

What is a variable?

A factor which can change or be changed in an experiment.

What is volume?

The amount of room something takes up. Often measured in cubic centimetres (cm³).

What is an alkali?

A substance that turns litmus blue. It has a pH of more than 7.

What is a chemical reaction (change)?

A change in which one or more new substances are formed.

What is evaporation?

When a liquid changes into a gas.

What are metals?

An element that is shiny when polished, conducts heat and electricity well, is malleable and flexible and often has a high melting point.

What is a mixture?

Two or more substances jumbled together but not joined to each other. The substances in mixtures can often be separated from each other.

What is a physical change?

A change in which no new substances are formed, e.g., changes of state.

What is a property?

A description of how a material behaves and what it is like. Hardness is a property of some solids.

What is an atom?

A small particle from which all substances are made.

What is carbon dioxide?

A waste gas produced by respiration.

What is a compound?

Substance that can be split up into simpler substances, since it contains the atoms of two or more elements joined together.

What is an element?

A simple substance, made up of only one type of atom.

What is a molecule?

Two or more atoms joined together in group of a set size.

What are particles?

The tiny pieces of matter that everything is made out of.

What is a periodic table?

An ordered list of all known elements.

What is pure?

A single substance that does not have anything else in it (rather than a mixture of substances).

What is a convention?

A standard way of doing something or representing something, so that everyone understands what is meant.

What is the Earth's crust?

The solid layer of rocks on the surface of the Earth.

What does it mean to recycle?

Using a material again, often by melting it and using it to make new objects.

What is a resource?

Something that is used and needed (often to make something new).

What is a solid?

One of the states of matter. Has a fixed shape and fixed volume.

What is a symbol?

The letter or letters that represent an element.

What is boiling point?

The temperature at which a liquid boils.

What does it mean to be brittle?

Not easily bent, or not flexible, breaks under force.

What is a conductor of electricity?

A substance that allows electricity to pass through it easily.

What is a conductor of heat?

A substance that allows heat to pass through it easily.

What does it mean to be ductile?

A ductile material can be pulled into a wire, without breaking.

What does it mean to be flexible?

Able to bend without breaking.

What is an insulator?

A material that does not allow something to pass through it (e.g. heat, electricity).

What is a liquid?

One of the states of matter. Has a fixed volume but not a fixed shape.

What does it mean to be malleable?

Able to be beaten and bent into shape.

What does it mean to be magnetic?

A material, such as iron, that is attracted to a magnet.

What is melting point?

The temperature at which a solid turns into a liquid.

What are metals?

Elements that are shiny when polished, conduct heat and electricity well, are malleable and flexible and often have high melting points.

What are non-metals?

Elements that are not shiny, and do not conduct heat and electricity well.

What is reactivity?

How easily a substance takes part in chemical reactions. Some substances are more reactive than others.

Who is a financial analyst?

Someone who looks in detail at the amount of money something costs to produce and compares it with the amount of money that can be made.

What is apparatus?

Pieces of equipment.

What is a carbonate?

Compound containing an element bonded with carbon and oxygen.

What is criteria?

A set of standards by which to judge things.

What is a product?

A new substance made in a chemical reaction. Products are written on the right side, after the arrow, in a word equation.

What are reactants?

A substance that takes part in a chemical reaction. Reactants are written on the left side, before the arrow, in a word equation.

What is thermal decomposition?

Breaking down a compound into simpler substances using heat.

What is a word equation?

An equation in which the names of the reactant(s) are written on the left side, there is an arrow pointing from left to right and the names of the product(s) are written on the right side.

What is population?

The number of a certain organism found in a certain area (e.g. the number of people living in a town).

What does it mean to be toxic?

A toxic substance is poisonous.

What is a bond?

A force that holds some atoms tightly together.

What is energy?

Something that is needed to make things happen or change.

What is a mineral?

A naturally occurring element or compound that can form distinct grains in rocks. Some mineral compounds are important sources of metals.

What is ore?

A rock that contains enough of a certain metal, or mineral, to make it worth mining.