Chemistry Unit 7 Study Guide

1. You may use this study guide to review for your test; practice your new skills or review old concepts. Each topic has several questions relating to it, this should help with giving you plenty of practice. ChemistryUnit 7Study Guide

3. Gram Formula Mass A What is the gram formula mass for CaSO4? 136 g/mole

4. Gram Formula Mass B What is the gram formula mass for Al(OH)3? 78 g/mole

5. Gram Formula Mass C What is the gram formula mass for Cu(NO3)2? 188 g/mole

6. Gram to Mole A How many moles are there in 55 g of H2O? 55 g H2O / 18 g/mole = 3.1 mole

7. Gram to Mole B How many grams does 3.1 moles of H2SO4 contain? 3.1 mole x 98 g/mole = 303.8 g

8. Gram to Mole C How many moles are contained in 2.65 g of O2? 2.65 g / 32 g/mole = 0.083 mole

9. Balance Equations A Balance the following equation: H2SO4 + NaBr → Na2SO4 + HBr 1:2:1:2

10. Balance Equations B Balance the following equation: Na + Cl2→ NaCl 2:1:2

11. Balancing Equations C Balance the following equation: Cu + HBr → CuBr2 + H2 1:2:1:1

12. Molarity A What is the concentration of a solution containing 0.5 mole of NaCl in 2.4 L of water? 0.21 M

13. Molarity B What is the formula for Molarity? M = moles of solute/ L of solution

14. Molarity C What is the concentration of a 0.25 L solution with 44.5 grams of MgSO4? 44.5 grams/120g/mole= 0.37moles; 0.37 moles/0.25L = 1.5 M

15. pH A How do we determine the pH of a solution? You take the –log of the hydrogen ion concentration (molarity).

16. pH B What is the relationship between pH and pOH? They are opposites; pH measures H ion concentration and pOH measures OH ion concentration, they add up to 14.

17. pH C If you have a M of 4.5 x 10-5 what is your pH? pH = 4.3

18. Redox A If an element is being reduced what is happening to it’s charge and to the electrons? Reduced elements are gaining electrons and therefore their charge is becoming more negative.

19. Redox B If an element is being oxidized what is happening to the electrons and the charge? Oxidized elements are losing electrons and therefore their charge is becoming more positive.

20. Redox C What is the relationship between an element being reduced and a reducing agent? They are opposites, if an element is being reduced it is gaining electrons and a reducing agent is losing electrons (it is the oxidized element)

21. Redox 2 A Given the following reaction identify the element that has been reduced. CaI2 + Cl2→ CaCl2 + I2 Cl was the reduced element because it gained 1 electron.

22. Redox 2 B Using the following reaction identify which element was oxidized and what the reducing and oxidizing agents are. 2KClO3 → 2KCl + 3O2 O went from -2 to 0 so it lost 2 electrons and was oxidized. That makes it the reducing agent and the Cl the oxidizing agent.

23. Redox 2 C From the following reaction identify the oxidation numbers (charges) for all of the elements. 2Na + Cl2 → 2NaCl 2Na = 0; Cl2 = 0; NaCl= Na= +1, Cl= -1

24. Solubility A What is the Ksp for the following reaction? 2HBr→ H2 + Br2 Ksp= [H2][Br2]/[HBr]2

25. Solubility B If a reaction has a Ksp of less than 1 what can we say about this solution? The solid is relatively insoluble and the reaction will proceed to the left.

26. Solubility C Complete the following generalization: The higher the Ksp of a solution the _____soluble the solute is. more

27. Vocabulary A What does an oxidizing agent do? An oxidizing agent pulls the electrons from a different element from within a chemical reaction.

28. Vocabulary B Explain the difference between a solute and a solvent. The solute is the substance that you are dissolving and the solvent is what you are dissolving in and usually is the higher quantity.

29. Vocabulary C What is an oxidation number? It is the charge that an ion has.

30. Acids/Bases A What ions do acids and bases typically produce and do they always have to produce those ions? Acids produce H ions and bases produce OH ions however you can also classify acids and bases by proton donor or acceptor. An acid is a proton donor and a base is a proton acceptor.

31. Acids/Bases B What result should we get from an acid on the litmus test? An acid should turn blue litmus red.

32. Acids/Bases C If we have the same molarity of HCl and H2SO4 which acid will titrate a base to the endpoint faster and why? H2SO4 because it donates 2 H+ for every molecule.

33. Factors Affecting Solubility A What are two factors that affect solubility of a solute in a solvent? Ionic character of the solute, Concentration, Electrical nature

34. Factors Affecting Solubility B Explain how concentration affects a solute’s solubility? The more ions you have in a solution the more solvent is being used to dissolve the solute until you reach saturation.

35. Factors Affecting Solubility C How does the electrical nature affect solubility? A polar compound is likely to conduct an electrical charge while a nonpolar compound is not. And because of our “like dissolved like” rule you must have a conductor dissolved in a conductor or vice versa.

36. Titration A What is titration? The process of neutralizing an acid or base by using a solution with known concentration until an endpoint is reached. Usually indicated by an acid/base indicator.

37. Titration B If we are neutralizing NaOH by using HBr what is the ratio of the ions to each other? 1:1; for every one OH there is one H produced by HBr.

38. Titration C If we are neutralizing Al(OH)3 what will the ratio of HBr be and why? 1:3 because the base is producing 3 OH and our acid is only producing 1 H so we will need 3 times as much.