Class TAKS Review Objective 4

1. Class TAKS Review Objective 4 Matter and Change

2. Matter Anything that has mass and takes up space. Energy is NOT matter

3. Matter is divided into 3 types: Elements Compounds Mixtures

4. The 3 types can be further separated in two categories: Pure Substances Elements are the simplest pure substances Mixtures are not pure substances and we will deal with them tomorrow.

5.  Cannot be broken down into simpler substances. All atoms of an element have the same number of protons. There are 109 of these currently listed and named on the Periodic Table

6. 4 Basic Types ofElements Metals: found on the left and center of the Table of Elements Non-metals: found on the right side of the Table of Elements Metalloids: found along the stair-step line Synthetic: made in the laboratory and not yet found in nature – many of the Actinide and Lanthanide series and very large # elements.

7. The BOHR Model of an Atom This is the first model to have a nucleus with protons and neutrons. The electrons are in various energy levels and circle the nucleus. Model most people draw today.

8. Drawing a Bohr Model of Lithium Center (blue) circle is the nucleus. It should contain: 3+ and 4N to represent the 3 protons and 4 neutrons. The orange circle gets 2e-, and the purple gets 1e-.

9. Atoms are. . . The smallest part of a single element. The basis of all matter. Made of mostly empty space. Have a positive core or nucleus. Have electrons in orbit in clouds.

10. 23 According to the periodic table, which element most readily accepts electrons? A Fluorine B Nitrogen This is a nonmetal, so it accepts electrons but it will also share them as in NO31-. C Arsenic This is a metalloid, so it only sometimes accepts electrons. D Aluminum This is a metal so it donates electrons.

11. What about MOLECULES? These are MULTI-ATOM particles

12. Properties of Elements - Metals Metals are: Conductors Lustrous Electron donors Malleable Ductile

13. Where are the metal elements?

14. Properties of Nonmetals Nonmetals are brittle, insulators, electron acceptors Usually form negative ions (except H) Many are gases at room temperature Found to the right of the stair-step line

15. Diatomic Elements – Nonmetals that come as molecules 7 Elements are di- (2) atomic (atoms) The easy way to remember them is by the name Br I N Cl H O F

16. 3 Which of the following groups contains members with similar chemical reactivity? A Li, Be, C B Be, Mg, Sr C Sc, Y, Zr D C, N, O

17. Lets look at the Table provided. To have similar chemical properties of any kind, they must be in the same Group or Family. Groups are columns, so the answer would be B

18. T y p e s o f m a t t e r C o m p o u n d s - Pure substances that can be broken down by a chemical change. Molecules are the smallest particle of a compound that retains its properties and it is composed of 2 or more atoms.

20. Names of Compounds – Ionic Ionic compounds consist of cations (positive ions) and anions (negative ions). A Roman numeral in parentheses, preceded by the name of the element, is used for elements that can form more than one positive ion. This is usually seen with metals. Fe2+ Iron (II) Cu+ Copper (I)Fe3+ Iron (III) Cu2+ Copper (II)

21. Ionic compounds – naming cont. The -ide ending is added to the name of a single element when it becomes an ion of that element. Oxide, Nitride, Sulfide etc. Some polyatomic anions have a names ending in -ite for the lower # of oxygens and –ate for more oxygens. NO2 nitrite NO3 nitrate

22. Covalent Compounds – Names are the Formulas These are nonmetal to nonmetal compounds. The name tells you the formula. Carbon dioxide 1 C and 2 O CO2

23. Special Names of Compounds Acids and Bases Bases end in the hydroxide anion OH- They are named with the metal and hydroxide. NaOH is sodium hydroxide Acids that are two elements are named Hydro-nonmetal –ic Acid such as HCl hydrochloric acid Group -ate becomes –ic and -ite becomes –ous. H2SO3 sulfurous acid H2SO4 sulfuric acid

25. What doesn’t matter to the test? A The amount of vitamin C in each tablet This should be a controlled variable! B The severity of the patients’ cold symptoms This would be very hard to control, but a large experimental group should allow for differences C The chemical formula for vitamin C Compound formulas NEVER change so this is our answer it is irrelevant!!! D The amount of time before symptoms improve This is what we are testing, it is most relevant.

26. Density = Mass / Volume THIS IS FROM THE FORMULA PAGE 25 A block of maple wood with a volume of 405 cubic centimeters and a density of 0.67 g/cm3 is sawed in half. The density of the two smaller blocks is now — A one-fourth the original density B one-half the original density C two times the original density D the same as the original density

27. Changes in Matter – Physical or Chemical? Physical changes are changes in the state of matter. They do not change the substance. (Melting, boiling, condensing, freezing, cutting) Chemical changes are reactions that result in new products with new properties.

29. Law of Conservation of Matter Matter can not be created or destroyed. The total mass of the substances before they are mixed is equal to the total mass as a mixture.

30. Chemical Reactions Since matter can not be created or destroyed, chemical reactions must be balanced in terms of mass. The amount of mass you start with must be equal to the mass of the products. Reactants ? Products 100g total = 100g total

31. 39 According to the law of conservation of mass, how much zinc was present in the zinc carbonate? A 40 g B 88 g C 104 g D 256 g

32. Chemical Equations Whole numbers written in front of formulas are called coefficients. For example, 4 C6H12O6 indicates that there are 4 molecules of glucose sugar. To determine how many total atoms of each element are present, multiply the coefficients by the subscripts for each element. 4 C6H12O6 would contain 24 atoms of carbon (4 x 6), 48 atoms of hydrogen (4 x 12), and 24 atoms of oxygen (4 x 6).

33. To balance equations: The number of atoms of each type of element on the reactant side (left of the arrow) must be equal those on the product side (right side of the arrow). 2 H2 + O2 2 H2O There are 4 hydrogen atoms on the left (2 H2) and 4 hydrogen atoms on the right (2 H2O) There are 2 atoms of oxygen (O2) on the left and 2 atoms of oxygen on the right (2 H2O). When a subscript is missing, it is understood to be 1.

34. K + H2O ? KOH + H2 19 What is the coefficient for H2O when the above equation is balanced? A 1 B 2 C 3 D 4

35. Balance the equation below, the boxes should get the coefficients.

36. The 3 types can be further separated in two categories: Pure Substances Elements are the simplest pure substances Mixtures are not pure substances. Each part of a mixture keeps its own properties, and can be separated out by a physical change.

37. Decide if the substance is Element, Compound , or Mixture?

39. Changes in Matter – Physical, Chemical or Nuclear? Physical changes do not change the substance. The state of the matter may change, but it keeps its own properties. Cutting a piece of wood does not change the wood, it is simply smaller. Chemical changes are also called chemical reactions. When a different substance is produced than what was present at the start, a chemical change has occurred.

40. Nuclear Changes: Fission and Fusion Fusion occurs when the nucleus of one atom is joined by the nucleus of another. This is the reaction that occurs on the sun and stars. It produces extreme energy release. Fission occurs when the nucleus of an atom ejects particles and energy when hit by a subatomic particle such as a neutron. This also causes a release of extreme energy and is the basis of atomic energy plants and bombs.

41. There are two types of mixtures: Heterogeneous- mixture is not the same from place to place. Chocolate chip cookie, gravel, soil. Homogeneous- same composition throughout. Kool-aid, air, brass.

42. P r o p e r t i e s o f M i x t u r e s : E a c h s u b s t a n c e r e t a i n s i t s o w n p r o p e r t i e s . S u b s t a n c e s c a n b e p r e s e n t i n a n y a m o u n t . S u b s t a n c e s c a n b e s e p a r a t e d b y s i m p l e p h y s i c a l m e a n s.

43. Separating Mixtures – Physical Changes Separation of mixtures could be: Magnetic removal (if there is Fe, Ni, Co) Filtration (if there are large particles) Hand sorting particles Decanting (pouring off the less dense liquid)

44. Another technique for  separating mixtures: Evaporation: changing from a liquid to vapor state– leaves behind the other component.

45. Distillation: Process used to remove vapor from liquid by heating Great for separating two or more liquids which have different boiling points.

46. So, what is a suspension or colloid? Colloids have small particles that are not visible by just looking. An example would be coffee. However, they show the Tyndall Effect (see the laser light line). They can not be separated by filtering.

47. Solutions: 2 parts S o l v e n t - t h e m o s t a b u n d a n t s u b s t a n c e i n t h e s o l u t i o n . S o l u t e - t h e l e a s t a b u n d a n t s u b s t a n c e i n t h e s o l u t i o n . Homogeneous: You can not see any particles of either part!

48. The three methods to increase the rate of solution for a solid are? Heat it! Crush it! Stir it!

49. 17 All of these can affect the rate at which a solid dissolves in water except — A decreasing air pressure B stirring the water C increasing the temperature of the water D using larger crystals of the solid

50. The three methods to increase the rate of solution for a solid are? Heat it! C Crush it! D slows it Stir it! B So this eliminates choices B, C & D Which will NOT change it? A Answer choices were: A decreasing air pressure B stirring the water C increasing the temperature of the water D using larger crystals of the solid

51. Solubility Factors –  What will dissolve? Solubility Rules 1. All sodium, potassium, and ammonium salts are soluble. 2. All silver, lead, and mercury salts are insoluble. 3. All carbonates, sulfides, and hydroxides are insoluble. 4. All nitrates and sulfates are soluble except calcium sulfate and barium sulfate.

52. 10 A 0.2 g crystal of gypsum dissolves very slowly in 100 mL of water while the water is stirred. Which of these would cause the gypsum to dissolve faster? F Decreasing the water temperature G Stopping the stirring H Lowering the air pressure J Crushing the crystal What are the 3 ways to increase the rate at which a solid dissolves? Heat it! Crush it! Stir it! ANSWER? J

53. How much solute will dissolve? A solubility curve shows the amount of each solute that will dissolve in 100g H20 at each temperature. Saturated is on the line. Unsaturated is below the line. Supersaturated is above the line.

54. 51 At which temperature do KBr and KNO3 have the same solubility? A 27°C B 48°C C 65°C D 80°C

55. Try this one!

56. Concentrated or Dilute? A concentrated solution has as little solvent as possible. A dilute solution has added solvent. After adding more solvent, there is still the same mass of solute that you started with.

57. pH is a measure of the  Strength of Acids & Bases Acids have 0-6.99 pH Bases have 7.01-14 pH Remember because A begins the alphabet and zero begins numbers Litmus turns red in acids and blue in bases Phenothalein turns pink in a base and stays clear in acids.

58. Higher pH levels means? 33 Two clear solutions are placed in separate beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. If the two solutions are mixed and the resulting pH is 5, the second solution must have — A fewer suspended solids B a lower temperature C more dissolved salt (NaCl) particles D a higher concentration of OH– ions

59. Chemical Reactivity Metals increase in reactivity left and down. Nonmetals become more reactive up and to the right. Most reactive metal is? Most reactive nonmetal is?

60. Now its your turn! Answer on your own paper the questions from the handout. We will check your answers before you leave.