Elements, compounds and mixtures

Section 1 from the Edexcel IGCSE Chemistry Specification - principles of chemistry

What are particles that make up everything?

Atoms

Water and sugar is an example of what kind of mixture?

A solution.

What is a molecule?

When more than one atom bonded together (can be the same type or different types).

Water with chalk is an example of what mixture?

A suspension.

What is an element?

A substance made up of only one TYPE of atom

Water and milk is an example of what type of mixture?

A colloid

What are compounds?

Substances made up of two or more elements CHEMICALLY COMBINDED/BONDED/JOINED together (such as methane).

What is the term for substances made up of two or more elements and/or compounds NOT chemically bonded together?

A mixture

What are the size of particles in a solution?

less than 1 nm

Which sort f mixture’s particles are usually larger than 1000nm?

suspension

What is the name given to the effect where you can see the path of light through a mixutre?

Tyndall effect

Why doesn’t the Tyndall effect last long in a suspension?

The particles fall to the bottom when left to sit for a while so the Tyndall effect doesn’t last long.

Which is a type of mixture that has a uniform composition throughout, meaning its components are indistinguishable and evenly distributed?

homogeneous mixture

What does heterogeneous mean?

Heterogeneous mixtures have a non-uniform distribution of components, leading to varying compositions in different parts of the mixture.

How many micrometres are there in a nonometre?

0.001

How many micrometres are there in a millimetre?

1000

What is another name for salt water?

Saline solution

What happens to a pure substance as 100 degrees Celsius?

It starts to boil

What is the melting point of a pure substance?

0 degrees Celsius

Impure substances melt/boil over a range of….?

Temperatures

Temperature doesn’t rise until all of the pure substance has been….?

melted

Is Styrofoam a suspension, colloid or solution?

colloid

Is a solution transparent, translucent or opaque?

Transparent