Entry Task: October 3 rd- 4 th Monday

1. Entry Task: October 3rd-4th Monday Question: What is the difference between a heterogeneous mixture and homogeneous mixture You have 5 minutes!

3. Physical and Chemical Properties

4. I Can… -Distinguish between a physical-chemical properties and changes. -Apply the law of conservation of mass to chemical reactions. -Distinguish between homogeneous and heterogeneous mixtures. -Compare and contrast compounds, elements, and atoms.

5. Substances Substances- are matter that has a uniform and UNCHANGING composition Example: Water- pure water- is uniform (same through out) and its composition will ALWAYS be H2O

6. Physical Properties Physical properties- are characteristics that can be observed or measured without changing the samples’ composition. color odor solubility density conduction luster melting point malleable phase- at room temperature boiling point

7. Physical Properties What is the difference between extensive and intensive properties? Extensive properties are dependent upon the amount of substance that is there. Example- length, volume, shape Intensive properties are independent of the amount of substance present. Example- density, or melting point or boiling point

8. What are chemical properties? Chemical properties describes the ability of a substance to react with another substance. Ability to catch on fire (flammability) Ability to rust (corrosion) Ability to burn skin (acid)

9. States of Matter Very close together Definite Definite Undefined- shape of container Particles slide past each other Defined Undefined- shape of container Undefined- Volume Compressible Particles are very very far apart

10. Physical Change When the appearance changes but not the composition of the substance remains the same is called a physical change. Water is still water whether it’s a solid (ice) or gas (steam) Hair is hair whether its long or cut short Example: Freezing, cutting, crumpling, breaking, crushing and boiling

11. Chemical Changes A process that involves one or more substances changing into new substances is called a chemical change. Examples- rusting car, burning paper, rotting food, tarnish. 4Fe (solid) + 2 O2 (gas) 4FeO (rust)

12. How do you know if it’s going through a chemical change? When observing a “change” at least 2 of these have to be present. Temperature change Presence of a gas (bubbles) Color change Odor change Precipitate- solid floaters

13. Law of Conservation of mass • That mass is neither created nor destroyed during a chemical reaction- it is conserved

14. Law of Conservation of mass A chemical change results in a new substance being formed. What happens to the individual atoms during a chemical change? They rearrange to form a new substance. 2 molecule of H2O- water + Hydrogen molecule – H2 Hydrogen molecule – H2 Oxygen molecule – O2

15. 6. From a laboratory process designed to separate water into hydrogen and oxygen gas, a student collected 10.0 g of hydrogen and 79.4 g of oxygen. How much water was originally involved in the process? If 10 grams of hydrogen and 79.4 grams of oxygen are collected, that means there is 89.4 grams of water to start.

16. 7. A student carefully placed 15.6 g of sodium in a reactor supplied with an excess quantity of chlorine gas. When the reaction was complete,the student obtained 39.7 g of sodium chloride. How many grams of chlorine gas reacted? How many grams of sodium reacted? 39.7 grams of sodium chloride was obtained. 15.6 of it was sodium so that makes 24.1 grams of chlorine was used. 15.6 grams of sodium.

17. 8. In a flask, 10.3 g of aluminum reacted with 100.0 g of liquid bromine to form aluminum bromide. After the reaction, no aluminum remained, and 8.5 grams of bromine remained unreacted. How many grams of bromine reacted? How many grams of compound were formed? 10.3 g aluminum + (100g – 8.5 g= 91.5g) bromine = 101.8 grams of aluminum bromide

18. 9. A 10.0-g sample of magnesium reacts with oxygen to form 16.6 g of magnesium oxide. How many grams of oxygen reacted? 10 g of magnesium – 16.6 grams of magnesium oxide = 6.6 g of oxygen

19. Matter is sorted… By composition. What its made out of What are the two broad categories of separating matter? Mixtures AND Substances

20. Matter Mixtures Substances

21. Provide at least 5 examples. Spices blood brass Dirt Pizza

22. What are mixtures? A mixture is a combination of two or more substances in which each of the substances retain their identity. They can be separated by physical means.

23. Two kinds of Mixtures Define heterogeneous mixture. A mixture that is NOT evenly distributed. These types of mixtures have two or more compositions and are called heterogeneous mixture. It can be very obvious-like a salad or difficult to catch- orange juice (pulp). These mixtures can be separated by physical means.

24. Define homogeneous mixture. A mixture that IS evenly distributed. Homogeneous mixtures are composed of one composition. Homogeneous mixtures are the same composition through out the mixture. Solutions ARE homogeneous mixtures. What are some types of solutions? These mixtures can be separated by physical means.

25. Matter Mixtures Substances Chemical physical Homogeneous-(Solutions) Heterogeneous Same through out Not the same through out

26. Sodium Chloride What are compounds? Are types of pure matter that can be broken down into simpler substances. What are elements? Are types of pure matter that can not be broken down into simpler substances. Elements are the simplest form of matter.

27. Matter Mixtures Substances Fixed composition/properties physical Chemical Homogeneous-(Solutions) Heterogeneous Same through out Compounds Elements Not the same through out Can be broken down Can’t be broken down H2O H2O2 CO2 H2 O2 C

28. Examples of Substances C12H22O11Sugar NaCl Salt Au gold Cl Chlorine I Iodine C3H7OH Alcohol H2O Water CO2 Dry Ice S Sulfur Na Sodium O Oxygen

29. Sort the substances Elements Compounds I Iodine C12H22O11 Sugar Cl Chlorine NaCl Salt O Oxygen S Sulfur CO2 Dry Ice C3H7OH Alcohol H2O Water Na Sodium Au gold

30. Regardless of the amount, a compound is always composed of the same elements in the same proportion by mass. Define Law of definite proportions- Law of multiple proportions H2O- 2 grams come from hydrogen and 16 grams of oxygen. Basically- that different compounds CAN be made of the same elements but in different proportions. H2O2 and H2O

31. I can…Trace the history of the discovery atom and the theories behind it.Explain the relationship between proton, electron and neutrons with atomic number and atomic mass.Define an isotope and explain why atomic masses are not whole numbers

32. Ch. 4 pg. 87-104- The structure of the Atom

33. Background on the Atom Greek philosophers organized matter into combinations of 4 fundamental elements and how each changes into one another:

34. Summarize Democritus’s ideas about the atom • Matter composed of empty space in which atoms moved. • Atoms were solid, homogeneous and indestructible, and indivisible. • Different kinds of atoms have different sizes and shapes. • Differing properties of matter were due to the size, shape and movement of atoms. • Apparent changes in matter were a result of groups of atoms not changes in the atoms themselves.

35. 2000 years later…

36. Summarize Dalton’s ideas about the atom. • All matter is made up of atoms. • All atoms in a given element are identical, having same size, mass and chemical properties- different from atom of other elements • Atoms cannot be created, divided into smaller parts, or destroyed. • Different atoms combine in simple whole number ratios to form compounds • In a chemical reaction, atoms are separated, combined, or rearranged.

37. Define atom • The smallest particle of an element that retains the properties of the element is called an atom

38. In the 1800’s most scientist believed that the atom as a teeny tiny solid sphere that was not made of anything smaller

39. What is a cathode? • It’s the negative terminal of a battery. What is a anode? • It’s the positive terminal of a battery.

40. What is a cathode ray? • A Cathode ray is a vacuum tube that had a positive end (anode) and a negative end (cathode) in which particle from the cathode traveled to the anode end creating a flash of light

41. Variations to the cathode ray Because the cathode ray is deflected towards the positively charged plate by an electric field, the particles in the ray must have a negative charge.

42. By the end of the 1800’s, what were scientists fairly convinced of? • Cathode rays were actually a stream of particles • The particles carried a negative charge. (The exact value of the negative charge was not known, however.)

43. Summarize J.J. Thomson’s experiment that leads to the discovery of the electron. • Tried to determine the mass of 1 particle in the cathode beam. • Determined the mass-charge ratio • Found that his particle had a much lower ratio than hydrogen- the lightest known atom. • This means there are particles smaller than an atom. • Daltons theory is wrong- atoms are divisible.

44. Summarize Millikan’s experiment. • Determined the exact charge to mass ratio of an electron • He found that a single electron has a mass of an electron is 9.1 X10-28th the mass of hydrogen. • This means that it would take 1840 electrons to have the mass of 1 atom of hydrogen.

45. Evidence for models of the atom • Atoms are made of negative particles • Since our world is neutral (electrically) there HAS to be a complementary positive particle to balance this out. • The positive particle has not been discovered yet so what does the atom “look” like”. Plum Pudding model.

46. Plum pudding model

47. Summarize Rutherford’s experiment. • Aimed a beam of alpha particles at a thin layer of gold foil and zinc sulfide detector behind it would detect the particles path as is went through the foil.

48. Summarize Rutherford’s experiment. • Expected minor deflections by the tiny electrons and because the positive charge was uniform in the atom that that would not cause any deflections either.

49. Describe Rutherford’s nuclear model of the atom. • Result: mostly no deflections and some major deflections occurred. • Atom is mostly empty space and there is a dense region in the middle (nucleus) which contained all the positive charge for an atom and most of the mass

50. Define proton. • It’s a subatomic particle carrying a charge equal to but opposite that of an electron; that is, a proton has a positive charge of 1+. Define neutron. • It has a mass equal to a proton but carries no electrical charge- neutral.