What is the difference between mass and weight?

Mass O Quantity of matter O Measured with a balance O How much “stuff” is there O Constant

Weight O Measure of force of gravity O Measured with a spring scale O Changes depending on where you are

Weight Changes O Weight depends on the mass of the two objects. For Example: Earth is a lot more massive than other planets, therefore the force of gravity pulling us to it is larger, even though we don’t really feel it. Weights change on different planets depending on size. Would we weigh less on the moon, or Earth?

The Moon! O Now, would we have a different mass reading for both places?

Law of Conservation of Mass O Mass cannot be created or destroyed

Law of Conservation of Energy O Energy cannot be created or destroyed

Law of Conservation of Mass- Energy O Total amount of mass and energy are constant in the universe O Mass and Energy can be converted to each other.

What is the difference between temperature and heat?

Temperature vs. Heat O Temperature: measure of average kinetic energy of particles O Heat: a form of energy that can change the movement of particles, or increase the temp.

Temperature O Measured in Celsius degree or Kelvin in Chemistry O Measured with a thermometer

Heat O Results from temperature difference O Measured in joules or calories O Measured with a calorimeter

Let’s Look at These Closer.. O Place one hand on the top of your desk, and one hand on the leg of the desk. Which feels colder?

Probably the Metal, but why? O Metal is a great conductor. It will steal warm energy from your body and move it throughout the metal. The heat is spread out and therefore makes the desk appear colder.

Is the metal actually colder? O No, it has been in the same room as the top all day, so they both have the same temperature, just a different way of adjusting to the temperature of your body when your hands are placed on both materials.

Why does it take your energy? O The desk is trying to reach equilibrium between your body temperature and the temperature that it is in the room.

Let’s Look at Matter O Material: O Mixture: O Phase:

Two Types of Mixtures O Heterogeneous: O Homogeneous:

Homogeneous Mixtures O A homogeneous mixture is called a solution. O Solutions have two parts O Solute: O Solvent:

Liquid Solutions O When a solid chemical is mixed with water to create a solution, it has a certain concentration, or molarity. The higher the molarity, the more particles are dissolved in the solution. Molarity can be shown with a large M.

Gas Solutions O Not all solutions are liquids! O Can you think of an example of a gas solution?

Air! O Air is composed of nitrogen, oxygen, and other gases O Depending on where you are from, it can also contain things like soot, pollen

Substances O Pure salt or Pure sulfur are homogeneous materials that never change composition O These are known as substances. O If a substance is composed of one kind of atom, this is what we know as elements. O If these elements come together, they form compounds.

Chemistry! O In Chemistry, we study two types of substances: Organic and Inorganic O We primarily look at inorganic substances in this class, but if you go on to other classes, you will learn more organic chemistry.

Physical Changes O Do not change chemical character O Ex: Changing shape, cutting, pulling O Melting or boiling

Physical Property O Behavior of a substance undergoing physical change O Length, color, temperature

Physical Properties O Extensive: depends on amount of matter O Mass O Length O Volume O Intensive: do not depend on amount of matter O Density O Malleability O Conductivity O Ductility

Chemical Changes O When a substance undergoes a change so that different characteristics are present O Ex: nitric acid and copper

Chemical Property O Behavior of a substance undergoing a chemical change O How things react with each other