PS 101 Kim Cohn address

Chapter 15 - Chemistry 2 How to Obtain Slides A CD-R disc can be checked out from the library – 2 hour reserve. The disc can be duplicated at the library. The disc can be duplicated at your house.

Chapter 15 - Chemistry 3 4th Grade Standards 2 Students know the role of electromagnets in the construction of electric motors, electric generators, and simple devices, such as doorbells and earphones. Students know electrically charged objects attract or repel each other. Students know that magnets have two poles (north and south) and that like poles repel each other while unlike poles attract each other.

Chapter 15 - Chemistry 4 From Yesterday The atomic number of an atom that contains 32 protons, 30 neutrons and 31 electrons is? How many protons and neutrons are there in U235? What is the difference in chemistry between an atom with one proton and no neutron to that which contains one proton and one neutron?

Chapter 15 - Chemistry 5 From Yesterday How many protons and neutrons are there in U 235 ? If U 235 emits an alpha particle (review – this is a particle that consists of 2 neutrons and 2 protons), what becomes of the original U 235 ?

Chapter 15 - Chemistry 6 About Chemistry Chemistry is the study of matter. This includes biological molecules. The industry is the 5 th largest in the US.

Chapter 15 - Chemistry 7 Phases of Matter Solid – definite shape, not easily deformed. Liquid – takes the shape of the container. Gas – will expand to fill the container.

Chapter 15 - Chemistry 8 Phases of Matter 2

Chapter 15 - Chemistry 9 Phases of Matter 3 If heat a solid eventually the interactions between the particles will be disrupted and the solid will liquefy. If heat a liquid enough it, some particles will gain enough kinetic energy to be able to escape the surface of the liquid and become a gas. Gas molecules move quickly (1500 km/hr) in a vacuum. In a room they hit each other and take longer to go from one place to another.

Chapter 15 - Chemistry 10 Phases of Matter 4 What is jello? What is an aerosol? The divisions between solid, liquid and gas allow for intermediate phases.

Chapter 15 - Chemistry 11 Today’s Demo What are the physical properties of this substance? How would you classify it, as a solid, liquid or gas?

Chapter 15 - Chemistry 12 Today’s Demo What are the physical properties of nitrogen? A odorless, colorless, tasteless gas at room temperature. What would happen if nitrogen were cooled?

Chapter 15 - Chemistry 13 Physical and Chemical Properties Physical properties – color, hardness, texture, phases, density, ability to conduct heat, electricity. When a physical change occurs a physical property will be different. For example, melting ice. Chemical change – a substance changes from one type of matter to another. For example, the rusting of iron.

Chapter 15 - Chemistry 14 Physical and Chemical Properties 2

Chapter 15 - Chemistry 15 Physical and Chemical Properties 3 CaOCaS6S26S2 6O 2

Chapter 15 - Chemistry 16 Physical and Chemical Properties 4 Physical properties – color, hardness, texture, phases, density, ability to conduct heat, electricity. Chemical change – a substance changes from one type of matter to another. Sometimes difficult to distinguish between a physical and chemical change.

Chapter 15 - Chemistry 17 Question Your brother has grown two inches. Is this a physical or chemical change? Take in Twinkies and convert to flesh and bone – chemical.

Chapter 15 - Chemistry 18 Elements, compounds and Mixtures 1 Material consisting of one type of atom is an element. Element usually means a large collection of one type of atom. Each element is designated by an atomic symbol. Hydrogen is H, helium is He, carbon is C, tungsten is W.

Chapter 15 - Chemistry 19 Question What us the symbol for hydrogen in Chinese? To help you here are some Chinese characters. H

Chapter 15 - Chemistry 20 Elements, compounds and Mixtures 2 How atoms are grouped in an element is an elemental formula. Hydrogen is found in nature as H 2 This formula means that hydrogen is found in nature with two hydrogen atoms bound together.

Chapter 15 - Chemistry 21 Elements, compounds and Mixtures 3 If different elements are bound together we get a compound. Two atoms of hydrogen can combine with one atom of oxygen to form water. The formula for water is H 2 O. The chemical and physical properties of water are different than either hydrogen (a gas) or oxygen (another gas). When did you see hydrogen and oxygen combine to form water?

Chapter 15 - Chemistry 22 Question Chlorine is a green gas with a pungent, choking odor. It is toxic when inhaled. It was the first poison gas ever used in warfare. Why is there no danger in eating salt, although salt is made up of one atom of sodium and one atom of chlorine?

Chapter 15 - Chemistry 23 Purification by Physical Means Filtration Example – Coffee from grounds Distillation Examples – Salt from sea water.

Chapter 15 - Chemistry 24 Classification of Matter Matter Pure ElementsCompounds Heterogeneous Mixture Homogeneous Mixture SuspensionSolution Impure

Chapter 15 - Chemistry 25 Naming Compounds – two elements The first element keeps its’ name. The next element has an “ide” on the end. Put in mono, di, tri, tetra to tell how many atoms. Example – NaCl Example – CaF 2 Example – N 2 O 4 Example – H 2 O

Chapter 15 - Chemistry 26 Questions 1 Solutions and suspensions- 1. pure or impure? 2. Homogeneous or heterogeneous? 3. Element or Compound?

Chapter 15 - Chemistry 27 Questions 2 SO 2 1. Sulfur dioxide or dioxymonosulfide? 2. Element or Compound? 3. Mixture or pure substance?

Chapter 15 - Chemistry 28 Question 3 Which of the next two slides represent water boiling?

Chapter 15 - Chemistry 29 Slide A

Chapter 15 - Chemistry 30 Slide B