HAPPY TUESDAY! Copy down tonight’s homework.

1. HAPPY TUESDAY! Copy down tonight’s homework. Check board to see if I think you owe any work on the recipe project. Cores 3 and 4: Take out your physical/chemical changes lab and be ready to take a few notes. Have your study guide answers on your desk.

2. Today, we will… Cores 3 and 4: take some notes on the Law of Conservation of Mass Everyone: Do a quick warm-up Preview the next week and a half Go over the study guide

3. While I take attendance and check homework: Start a new page of notes: 11/13 Obj: Explain the Law of Conservation of Mass Write these equations: 2NaHCO3 + CaCl2 →CaCO3+ 2NaCl + H2O + CO2 4Fe + 3O2 → 2Fe2O3

4. Warm-up (Cores 1 and 2) When is the test? When is the note card due? What topics are you still struggling with? Can you stay after school today or tomorrow for some extra help?

17. PROOF THAT A CHEMICAL CHANGE HAS HAPPENED: • Show that a new substance has been formed. • CLUES THAT SUGGEST A CHEMICAL CHANGE HAS PROBABLY HAPPENED: • Production of a gas, unexpected change in color or temperature

18. Reaction #1 – ziploc bag experiment 2NaHCO3 + CaCl2 →CaCO3+ 2NaCl + H2O + CO2 “mass” 2NaHCO3 + CaCl2 = 165.7g “mass” CaCO3,2NaCl ,H2O,CO2 =165.7g Lego equation: 2(PYBG3) + WR2 →WBG3+ 2(PR)+ Y2G + BG2

19. Reaction #2 – rusting reaction 4Fe + 3O2 → 2Fe2O3 “mass” 4Fe + 3O2 = “mass” 2Fe2O3 = Lego equation: 4B + 3(Y2)→ 2(B2Y3)

20. LAW OF CONSERVATION OF MASS • In a chemical reaction, atoms are not created, destroyed, or turned into other kinds of atoms. • The bonds that connect atoms together are broken and rearranged to make new substances.

21. Before you leave... Tell me everything you can about the possible products of a chemical reaction involving this awesome compound

22. Classification of Matter

24. Question 1 – 10 (#1) • All matter is either a ____ or a _______

25. Answer 1 – 10 • pure substance or a mixture

26. Question 1 – 20 (#3) • All mixtures are either ________ or ________

27. Answer 1 – 20 • homogeneous or heterogeneous

28. Question 1 – 30 (#2) • All pure substances are either _________ or _____________.

29. Answer 1 – 30 • elements or compounds

30. Question 1 – 40 (#5) • What is the difference between a pure substance and a mixture?

31. Answer 1 – 40 • A pure substance has only one kind of particle (one “ingredient”). Every group of atoms is exactly the same. • A mixture has more than one kind of particle (more than one “ingredient”). There are different kinds of groups.

32. Question 1 – 50 (#8) • identify the following substances as elements, compounds, homogeneous mixtures, or heterogeneous mixtures: • sugar dissolved in water * pure water • carbon dioxide * air • oxygen * fog in air • chocolate milk * baking soda • plain milk • a slug

33. Answer 1 – 50 • sugar dissolved in water homogeneous mixture • carbon dioxide compound • oxygen element • chocolate milk hetero-/homogeneous mixture • plain milk homogeneous mixture • a slug heterogeneous mixture • pure water compound • air homogeneous mixture • fog in air heterogeneous mixture • baking soda compound

34. Question 2 – 10 (#6) • What is the difference between an element and a compound?

35. Answer 2 – 10 • All of the atoms in a sample of an element are exactly the same. • There are different kinds of atoms in a sample of a compound, but all of the groups of atoms are the same.

36. Question 2 – 20 (not on the study guide) • Both compounds and mixtures have different kinds of atoms. What is the difference between a compound and a mixture?

37. Answer 2 – 20 • Since a compound is a pure substance, all of the particles (groups of atoms) are the same, even though there are different kinds of atoms. • In a mixture, there are different kinds of particles (groups of atoms).

38. Question 2 – 30 (#13) • How many atoms of each element is present in one molecule/particle of the following compounds? • N2 • H2SO4 • NaF • CaCO3 • LiOH • NH4NO3

39. Answer 2 – 30 • N2 - 2 atoms of nitrogen • H2SO4 – 2 atoms of hydrogen, 1 sulfur, 4 oxygen • NaF – one atom of sodium, one atom of fluorine • CaCO3 – one atom of calcium, 1 carbon, 3 oxygen • LiOH – 1 atom of lithium, 1 oxygen, 1 hydrogen • NH4NO3 – 2 nitrogen, 4 hydrogen, 3 oxygen

40. Question 2 – 40 (#21) • When the mitochondria in your cells produce energy, they carry out the following chemical reaction: • glucose + oxygen ---> carbon dioxide + water • On the left side of the equation, there are 6 carbons, 12 hydrogens, and 18 oxygens. • What does the Law of Conservation of Mass tell you about the atoms on the right side of the equation?

41. Answer 2 – 40 • There are 6 carbons, 12 hydrogens, and 18 oxygens. Whatever atoms go in to the reaction, the same atoms come out of the reaction.

42. Question 2 – 50 (#22) • What happens to the atoms when substances undergo chemical changes?

43. Answer 2 – 50 • The atoms themselves are not changed – atoms are not created, destroyed, or changed into different atoms. • The arrangement of the atoms changes to make new substances. Chemical bonds between atoms are broken and re-formed in new ways.

44. Question 3 – 10 (#4) • Solutions are ___________________ mixtures.

45. Answer 3 – 10 • homogeneous

46. Question 3 – 20 (#7) How can you tell if a mixture is homogeneous or heterogeneous?

47. Answer 3 – 20 A homogeneous mixture looks the same everywhere. It is well-blended. You can see different things in a heterogeneous mixture – the “ingredients” are not well-blended.

48. Question 3 – 30 (not on study guide) • You have a container that has matter that is made up of hydrogen and oxygen atoms. Does it have to be water?

49. Answer 3 – 30 • No, it doesn’t have to be water. It could be: • Water… • A mixture of water plus oxygen gas • A mixture of water plus hydrogen gas • A mixture of water plus oxygen gas and hydrogen gas • Hydrogen peroxide • A mixture of hydrogen peroxide plus water, etc.

50. Question 3 – 40 (#23) • Name one pure substance, one heterogeneous mixture, and one homogeneous mixture from your recipe.