2/25/2003J.Noller 2003 States of Matter The Effects of Energy on Matter

J.Noller 2003 Four States of Matter Matter has many properties. It can have PHYSICAL properties like different densities, melting points, boiling points, freezing points, color or smells. Physical properties are MEASURABLE Each chemical has UNIQUE measurable physical properties There are also CHEMICAL properties that define matter Chemical properties define how a substance combines/recombines with other substances

J.Noller 2003 Four States of Matter ‘State’ of Matter = ‘Phase’ of Matter Phase Change is a PHYSICAL Change Not a Chemical Change

J.Noller 2003 Solids One of the main characteristics of solids is that they hold their own shape In the same way that a solid holds its shape the atoms inside of a solid are not allowed to move around much. The solid atoms and molecules are trapped in their places. The atoms still spin and the electrons still move but the entire atom doesn't go anywhere. They just kind of jiggle in place.

J.Noller 2003 Solid to Liquid To change a SOLID into a LIQUID, you add ENERGY. HEAT is the easiest energy to find At a ‘Magic Temperature’ the Solid turns into a liquid. This is called the MELTING POINT If you remove heat, the liquid turns back into a solid Then it is called a FREEZING POINT MELTING POINT is a measurable physical property

J.Noller 2003 Liquids Liquids are an in-between phase of matter. They are right between solids and gases. One characteristic of a liquid is that it fills the shape of any container. Has volume, but NOT Shape Liquids cannot be compressed.

J.Noller 2003 Liquid to Gas Add ENERGY to a liquid and it becomes a GAS The special temperature when a liquid becomes a gas is called the BOILING POINT. The reverse is the CONDENSATION POINT. You might hear the term VAPOR. Vapor and gas mean the same thing. The word vapor is used to describe gases that are usually found as liquids (like water).

J.Noller 2003 GAS Gas is everywhere. There is something called the ATMOSPHERE. That's a big layer of gas that surrounds the Earth. Gases are random groups of atoms. Gases are really really spread out and the atoms and molecules are full of ENERGY, bouncing around constantly. Gases can be COMPRESSED because there is so much room between atoms/molecules.

J.Noller 2003 Gases The special temperature when a liquid becomes a gas is called the BOILING POINT. When you cool a gas it liquefies. When a gas becomes a liquid the speed and energy in the molecules drop and ATTRACTION forces allow the molecules to group together.

J.Noller 2003 EVAPORATION Sometimes a liquid can be sitting there and its molecules will become a gas. That's called EVAPORATION. All liquids can evaporate at room temperature and pressure. Evaporation is when there are atoms or molecules escaping from the liquid and turning into a vapor. Not all of the molecules in a liquid actually have the same energy. The energy you can measure is really an AVERAGE of all the molecules. Those with a lot of energy that build up enough power to become a gas and leave the liquid. When it leaves it has evaporated.

J.Noller 2003 Gas to Plasma A plasma can be made from a gas if a lot of energy is pushed inside. All of this extra energy makes the neutral atoms break apart into positively and negatively charged ions and free electrons. The electrons are pulled off of neutral atoms. They leave ions and electrons in a big gaseous ball

J.Noller 2003 Plasma Plasmas are a lot like gases The atoms are different because they are made up of free ELECTRONS and IONS of the element. You don't really find plasmas too often when you walk around.

J.Noller 2003 Plasma We said you wouldn't find plasmas anywhere. But maybe there are some right in front of you. Think about a fluorescent light bulb. They are not like regular light bulbs. Inside the long tube is a gas. When the light is turned on ELECTRICITY flows through the tube. This electricity acts as that special energy and charges up the gas. This charging and exciting of the atoms creates a glowing plasma inside the bulb.

J.Noller 2003 States of Matter ADD Melting Point Freezing Point Boiling Point Condensation Point

J.Noller 2003 Measurable Physical Properties All matter has ‘measurable physical properties’! Properties: Atomic Mass, melting point, boiling point, density, electro negativity, polarity, etc. The properties are UNIQUE to the element or compound If you know the properties, you know the substance!

J.Noller 2003 Examples of Properties Element or Compound Atomic Weight (AMU) Atomic Volume (cm 3 /mol) Melting point K Boiling point K Density (g/cm 3 ) Hydrogen K20.4 K Water K373K.997 Sugar (Sucrose) °C Gold K 3081 K19.32 Silver K 2428 K 10.5 Lead K 2024 K11.34 Salt (NaCl)58?801°C1465°C2170 kg

J.Noller 2003 Density Lab SubstanceMassVolumeDensity 1 Pc Clay 2 Pc Clay 1 Stick 2 Sticks 1 Penny 2 Pennies 1 Crayon 3 Crayons