States of Matter

Goal of the class To understand the properties of a solid, liquid and gas. Question of the day: What is surface tension? Previous answer: We can separate a mixture by filtration, magnetism, distillation and evaporation. Previous Question: How can we separate a mixture?

Introduction We can all think of examples of solids, liquids and gases. They can be elements, compounds or mixtures. Examples include: Solid: Gold (element) Liquid: Water (compound & molecule) Gas: Air (homogeneous mixture) There states are defined NOT by what they are made of, but whether or not they can hold their volume and shape.

Solids Imagine you had a diamond and you picked it up. Then placed it in a bowl. Would the diamond change size or shape? A solid has a definite shape and volume. No, of course not

Particles in a Solid The particles in a solid are packed close together in fixed locations. If the arrangement of particles are in a regular pattern we call this a crystalline material, such as quartz.

Particles in a Solid In an amorphous solid the particles are in an irregular patter.

Liquids A liquid has a definite volume but no fixed shape. So if I pour 500 mL of milk from a square milk carton into a round glass. The amount of milk is still 500 mL, it’s just a different shape now. Equivalent volumes example.

Particles in a Liquid The particles in a liquid are packed closely, like in a solid. However, in a liquid they are free to slide over one another. A liquid is also called a fluid, meaning a substance that flows. Similar to if you hold a bag of marbles. They are all close together and free to move. Volume is the same and the shape changes.

Liquid Properties Water and other liquids have a property called surface tension that acts like a skin. The water molecules want to be as close as to each other as they can. Water beading on surfaces. Strong attraction between water molecules Lab where the water looks too high

Liquid Properties Water beading on surfaces. Strong attraction between water molecules Lab where the water looks too high

Liquid Properties What shape is a water droplet? Water droplets are spherical

Gases Particles in gases move around very quickly with a lot of space between them, this means you can compress them very easily. Gases don’t just take the shape of their container they fill the space of the container that they are in. Balloon blowing up

Comparison

Vocabulary Crystal – Having a highly ordered arrangement of atoms in all directions. Amorphous – Lacking any long range order of its structure. Surface Tension – The ‘skin’ on a liquid from the attraction of the molecules. What does that tell you about water? It’s not an element.

Homework Please complete Chemical Building Blocks workbook page 11