Objective 4…TAKS 10 th and 11 th grades Home slide

1. Objective 4…TAKS 10th and 11th grades Home slide Home Questions from TAKS: periodic chart placement Questions from TAKS: balancing equations Questions from TAKS: water properties and solutions Questions from TAKS: physical and chemical change Questions from TAKS: density Interactive non-TAKS quizzes on the internet Link to 10th grade study guide Scroll to p.291 for objective 4 Link to 11th grade study guide Scroll to p.342 for objective 4

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3. Home periodic chart placement Back to per. chart

4. Home Back to per. chart If there are 4 electrons and 4 protons, the element’s atomic number is 4. The picture shows a model of the element — A fluorine B helium C beryllium D oxygen 5

5. Home Back to per. chart The elements from which of the following groups are most likely to react with potassium (K)? F Group 2 G Group 7 H Group 13 J Group 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Group 1 wants to give an electron to column (group) 17 28

6. An unidentified element has many of the same physical and chemical properties as magnesium and strontium but has a lower atomic mass than either of these elements. What is the most likely identity of this element? F Sodium G Beryllium H Calcium J Rubidium Home Back to per. chart Mass increases with each lower row. Elements in the same column share the same physical and chemical properties. 4

7. Back to per. chart Home These are the noble gases and they don’t like to bond to anything. The elements of which of these groups on the periodic table are most resistant to forming compounds? A Group 1 B Group 9 C Group 14 D Group 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 37

8. Elements in Group 16 of the periodic table usually — F form large molecules G gain electrons when bonding H act like metals J solidify at room temperature Home Back to per. chart These 3 columns gain electrons. They steal electrons. They need electrons. 10

9. 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 Home Back to per. chart Elements in the same column have the same properties and reactivity. 3

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12. According to the periodic table, which element most readily accepts electrons? A Fluorine B Nitrogen C Arsenic D Aluminum Home Back to per. chart 23

13. Home Back to per. chart Which of the following salts has the greatest solubility in water at 25°C? F CaCO3 G FeS H HgCl2 J KClO4 Calcium carbonate - insoluble because of rule 3. Iron sulfide - insoluble because of rule 3 Mercury chloride - insoluble because of rule 2. Potassium perchlorate - soluble because of rule 1 50

14. Home Back to per. chart An unknown silvery powder has a constant melting point and does not chemically or physically separate into other substances. The unknown substance can be classified as — A an element B a compound C a mixture D an alloy Compounds can be chemically separated. Mixtures and alloys can be physically separated. 29

15. Home Back to per. chart Oxygen (O2) is an example of — A an alloy B a molecule C a salt D a mixture An alloy is a mixture or solution of two metals. A molecule is two or more atoms bonded covalently together. Usually included in the bonds are C, P and the diatomic elements bonded together. A salt is a an ionic bond between a metal and non-metal. A mixture is two substances together but not bonding together. A compound can be two or more elements bonded together, with ionic or metallic bonds. 9

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17. Go to: Subscripts Home balancing equations Go to: Coefficients Go to: Conservation of mass Go to: Conservation of energy Balance equations

18. Home Balance equations According to this information, what is the chemical formula for aluminum sulfate? A AlSO4 B Al2(SO4)3 C Al3(SO4)2 D Al6SO4 23

19. Home The chemical formula for calcium chloride is — F Ca2Cl G CaCl H CaCl2 J Ca2Cl3 Balance equations 38

20. Home 2 2 Balance equations 1 1 1 1 1 lead 1 lead 2 oxygens ≠ 3 oxygens What are the coefficients that will balance this chemical equation? A 2, 1, 1 B 3, 4, 2 C 2, 2, 1 D 4, 3, 2 Put a 2 here to make an even number of oxygens. 1 lead 2 lead 2 oxygens ≠ 4 oxygens 2 lead 2 lead 4 oxygens = 4 oxygens 45

21. Home Balance equations 2 When the above equation is balanced, the coefficient for magnesium chloride is — A 0 B 1 C 2 D 4 25

22. Home Balance equations 2 2 2 1 1 1 1 1 Then we’ll need to put coffecients on this side of the arrow to finish balancing it out. To make the hydrogens ‘even’, We put the coefficient 2 here. And have a sum of 4 hydrogens, 2 potassiums and 2 oxygens What is the coefficient for H2O when the equation is balanced? A 1 B 2 C 3 D 4 19

23. Home Balance equations

24. Which chemical equation supports the law of conservation of mass? F 2H2O(l) H2(g) + O2(g) G Zn(s) + HCl(aq) ZnCl2(aq) + H2(g) H Al4C3(s) + H2O(l) CH4(g) + Al(OH)3(s) J CH4(g) + 2O2(g) CO2(g) + 2H2O(g) Home Balance equations 4 hydrogens ≠ 2 hydrogens 2 oxygens 2 oxygens 1 zinc 1 zinc 1 hydrogens ≠ 2 hydrogens 1 chlorine 2 chlorines 4 aluminums 1 aluminum 3 carbons 1 carbon 2 hydrogens ≠ 3 hydrogens 1 oxygen 3 oxygens 1 carbons 1 carbon 4 hydrogens = 4 hydrogens 4 oxygens 4 oxygens 32

25. To produce 4 molecules of sugar, a plant needs — F 6 molecules of hydrogen G 12 molecules of ATP H 18 molecules of water J 24 molecules of carbon dioxide Home Balance equations Multiply the whole reaction by 4. 4( ) 1 10 4 x 6 carbon dioxide

26. Home Balance equations

27. 100 g Home Balance equations Reactants → Products The chemical equation shows CaCO3 being heated. Which of these statements best describes the mass of the products if 100 g of CaCO3 is heated? A The difference in the products’ masses is equal to the mass of the CaCO3. B The sum of the products’ masses is less than the mass of the CaCO3. C The mass of each product is equal to the mass of the CaCO3. D The sum of the products’ masses equals the mass of the CaCO3. 29

28. Home If all the reactants in a chemical reaction are completely used, which of the following statements accurately describes the relationship between the reactants and the products? F The products must have a different physical state than the reactants. G The total mass of the reactants must equal the total mass of the products. H The reactants must contain more complex molecules than the products do. J The density of the reactants must equal the density of the products. Balance equations Reactants become Products 2H2 + O2  2H2O 20 grams + 10grams = 30 grams 40

29. When 127 g of copper reacts with 32 g of oxygen gas to form copper (II) oxide, no copper or oxygen is left over. How much copper (II) oxide is produced? F 32 g G 95 g H 127 g J 159 g Home Balance equations 127 + 32 = ? 40

30. Home Balance equations

31. Home Balance equations

32. 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 Home Balance equations 64 + 192 = 152 + ? 64 + 192 – 152 = ? 39

33. Home Balance equations

34. Balance equations Home

35. The energy not stored in the bonds of the carbon dioxide and water must have left in the form of heat. Home Balance equations ≠ + = + Reactants = Products Why is the sum of the products’ energy in this reaction less than the sum of the reactants’ energy? A Energy is given off as heat. B The products absorb available energy. C Energy is trapped in the reactants. D The reactants’ energy is less than the melting point of glucose. 37

36. After Home Balance equations The illustrations show a conservation-of-mass experiment. The solution in the beaker lost mass because — F materials have less mass at high temperatures G the mass of the reactants and products was less than 100 g H sodium sulfate (Na2SO4) is lighter than air J some of the water molecules turned into gas Before Some of the water evaporated because of the heat. After( less than 100 g) Before(100 g) 30 REACTANTS →Products The sum of the reactants = the sum of the products.

37. An inventor claims to have created an internal combustion engine that converts 100 kJ of chemical energy from diesel fuel to 140 kJ of mechanical energy. This claim violates the law of conservation of — F momentum G inertia H energy J mass Home Balance equations chemical energy = mechanical energy + heat 48

38. Back to water Home water properties Go to: Polarity Go to: Solubility of liquids, solid Go to: Solubility of gases in liquids Go to: Electrolytic behaviors of solutions Go to: pH

39. Back to water What characteristic of waterremains the same no matter what is dissolved in it? A The ratio of hydrogen to oxygen B The ability to refract light C The hydroxide ion concentration D The freezing temperature Home Water is defined as two hydrogens to one oxygen. If there were more or less of these elements, the compound would have a different name and not be water. The bending of light depends on temperature and whether there is any solute in the water. Usually, the amount of OH- and H+ ions are equal in pure water. Water that is not pure, such as with solutes, does not always freeze at 0oC. 41

40. Back to water Home Which factor makes water an effective solvent? F The presence of molecular oxygen G Its lack of covalent bonds H The polar nature of its molecules J Its abundance on Earth’s surface 24

41. Back to water polarity: a compound’s uneven distribution of electrons. Home What is polarity?

42. Back to water Home Polarity acts like magnets. polarity: a compound’s uneven distribution of electrons.

43. Back to water Home The hydrogens are attracted to the oxygens of another molecule. polarity: a compound’s uneven distribution of electrons.

44. Back to water Home What does polarity do? Causes water to expand when it freezes. ice

45. Fish survive through severe winters because of the property of water that allows water to — F form chemical bonds as it freezes, raising the water temperature below the ice G increase in density while it freezes, dissolving more oxygen from the air H expand when it freezes, creating a floating and insulating layer of ice J precipitate vital nutrients when it freezes, increasing the food supply Home Freezing water becomes less dense. The air above the ice may be very, very cold… even - 60oF. But the water beneath the ice is no colder than 33oF. The living things in the very cold water have adaptations for 33oF but may not be able to survive any colder water than that. 26

46. If the properties of water were to change so that the solid form was denser than the liquid form, organisms living in a cold pond environment would be less likely to survive because water would no longer — F dissolve enough oxygen from the air G produce solutions containing vital nutrients H remain neutral, instead becoming highly acidic J produce a floating insulating layer of ice Home 40

47. Back to water Salt ions being separated by collisions of water molecules during “dissolving.” Home

48. Back to water Home What are some solubility tricks? • Grind large pieces of solute into small pieces, thereby increasing surface area for the water molecules to collide into. • Raise the temperature to increase collisions of H2O’s into solute. • Stir or shake which increases the collisions. surface area: smaller particles have more surface area compared to one large particle.

49. Back to water Home surface area: smaller particles have more surface area compared to one large particle.

50. Back to water Home