SCIN131-Introduction to Chemistry-APUS-Lesson 6 Assignment

Part 1 of 3 - 20.0/ 20.0 Points Question 1 of 12 4.0/ 4.0 Points The solubility of solids in water:  A.decreases with increasing temperature.  B.is independent of the temperature.  C.increases with increasing temperature.  D.Solids are not soluble in water.  E.none of the above Answer Key: C Question 2 of 12 4.0/ 4.0 Points If you add 4.00 mL of pure water to 6.00 mL of 0.750 M NaCl solution, what is the concentration of sodium chloride in the diluted solution?  A.0.250 M  B.0.450 M  C.1.13 M  D.0.500 M  E.none of the above Answer Key: B Question 3 of 12 4.0/ 4.0 Points If the solubility of sodium chloride is 36 grams per 100 grams of water, which of the following solutions would be considered unsaturated?  A.3.25 moles of NaCL dissolved in 500 ml of water  B.5.8 moles of NaCl dissolved in 1 L of water  C.1.85 moles of NaCl dissolved in 300 ml of water  D.none of the above Answer Key: B Question 4 of 12 4.0/ 4.0 Points Why is NOT a good idea to drink seawater when people are lost at sea?  A.The seawater has fish urine in it and who wants to drink that?  B.The osmotic pressure builds up in the cells of your intestine until they potentially rupture.  C.The semipermeable membrane protecting your stomach is ruptured during osmosis.  D.The high concentration of salt forces water out of the cells lining your stomach and intestine.  E.none of the above Answer Key: D Question 5 of 12 4.0/ 4.0 Points What are the ion concentrations in a 0.12 M solution of AlCl3?  A.0.12 M Al3+ ions and 0.36 M Cl- ions  B.0.36 M Al3+ ions and 0.12 M Cl- ions  C.0.12 M Al3+ ions and 0.040 M Cl- ions  D.0.040 M Al3+ ions and 0.040 M Cl- ions  E.none of the above Answer Key: A

Part 2 of 3 - 12.0/ 20.0 Points Question 6 of 12 4.0/ 4.0 Points In the following reaction: HCO3- (aq) + H2O (aq) → H2CO3 (aq) + OH- (aq)  A.H2O is an acid and H2CO3 is its conjugate base.  B.HCO3- is an acid and OH- is its conjugate base.  C.H2O is an acid and HCO3- is its conjugate base.  D.H2O is an acid and OH- is its conjugate base.  E.HCO3- is an acid and H2CO3 is its conjugate base. Answer Key: D Question 7 of 12 0.0/ 4.0 Points Which of the following is NOT a property of acids?  A.Acids have a slippery feel.  B.Acids have a sour taste.  C.Acids dissolve many metals.  D.Acids turn litmus paper red.  E.All of the above are properties of acids. Answer Key: A Question 8 of 12 0.0/ 4.0 Points What is the [H⁺] in a solution that has a pH of 3.35?  A.4.5 × 10-5 M  B.2.2 × 103 M  C.1 × 103.35 M  D.3.35 × 10-14 M  E.none of the above Answer Key: A Question 9 of 12 4.0/ 4.0 Points Which of the following acids is a monoprotic, strong acid?  A.sulfuric acid  B.carbonic acid  C.hydrobromic acid  D.phosphoric acid  E.none of the above Answer Key: C Question 10 of 12 4.0/ 4.0 Points The Bronsted-Lowry definition of an acid is:  A.a proton donor.  B.produces H⁺ in solution.  C.a proton acceptor.  D.produces OH⁻ in solution.  E.none of the above Answer Key: A

Part 3 of 3 - 10.0/ 10.0 Points Question 11 of 12 5.0/ 5.0 Points Calculate the mass of glucose (C6H12O6) in a 105-mL sample of a 1.61 M glucose solution. Number of moles = Molarity * Volume in litres n = 1.61 * 0.105 = 0.17 moles  1 mole Glucose weighs 180 grams. As molar mass of  glucose is 180 0.17 moles weighs  0.17*180 = 30.6 grams Comment: great! Question 12 of 12 5.0/ 5.0 Points Predict the products of the following Acid reactions: A)H3PO4(aq) + NaOH (aq) → Na3PO4(aq) +  H2O   ; B)  H2SO4(aq) + BaO(s) →  BaSO4 (s)  +  H2O are the equations balanced? /NO Answer Key: H2O|Na3PO4, H2O|Na3PO4, H2O|BaSO4, H2O|BaSO4, no

Part 1 of 3 - 20.0/ 20.0 Points Question 1 of 12 4.0/ 4.0 Points If the solubility of sodium chloride is 36 grams per 100 grams of water, which of the following solutions would be considered unsaturated?  A.3.25 moles of NaCL dissolved in 500 ml of water  B.5.8 moles of NaCl dissolved in 1 L of water  C.1.85 moles of NaCl dissolved in 300 ml of water  D.none of the above Answer Key: B Question 2 of 12 4.0/ 4.0 Points Which of the following compounds is a strong electrolyte?  A.C4H8O2  B.C6H12O6  C.C7H14O5  D.Na C2H3O2  E.all of the above Answer Key: D Question 3 of 12 4.0/ 4.0 Points After you have completed the task of diluting a solution, which statement below must be TRUE?  A.The new solution has more volume but has a lower concentration than before.  B.The new solution has less volume but has a higher concentration than before.  C.The new solution has less volume but has a lower concentration than before.  D.The new solution has more volume but has a higher concentration than before.  E.none of the above Answer Key: A Question 4 of 12 4.0/ 4.0 Points What are the ion concentrations in a 0.12 M solution of AlCl3?  A.0.12 M Al3+ ions and 0.36 M Cl- ions  B.0.36 M Al3+ ions and 0.12 M Cl- ions  C.0.12 M Al3+ ions and 0.040 M Cl- ions  D.0.040 M Al3+ ions and 0.040 M Cl- ions  E.none of the above Answer Key: A Question 5 of 12 4.0/ 4.0 Points Why is NOT a good idea to drink seawater when people are lost at sea?  A.The seawater has fish urine in it and who wants to drink that?  B.The osmotic pressure builds up in the cells of your intestine until they potentially rupture.  C.The semipermeable membrane protecting your stomach is ruptured during osmosis.  D.The high concentration of salt forces water out of the cells lining your stomach and intestine.  E.none of the above Answer Key: D

Part 2 of 3 - 20.0/ 20.0 Points Question 6 of 12 4.0/ 4.0 Points Which of the following common bases is commonly used for manufacturing fertilizer?  A.NaHCO3  B.NH3  C.KOH  D.NaOH  E.all of the above Answer Key: B Question 7 of 12 4.0/ 4.0 Points What is the concentration of the hydronium ions in an acidic solution?  A.0.0 M  B.< 1.0 x 10-7 M  C.1.0 x 10-14 M  D.> 1.0 x 10-7 M  E.1.0 x 10-7 M Answer Key: D Question 8 of 12 4.0/ 4.0 Points Which of the following is NOT an acid-base conjugate pair?  A.H2CO3 and HCO3-  B.NH4+ and NH3  C.H2S and OH-  D.H2O and OH-  E.none of the above Answer Key: C Question 9 of 12 4.0/ 4.0 Points Which of the following acids is commonly used for manufacturing fertilizer?  A.HBr  B.HNO3  C.HCl  D.HF  E.all of the above Answer Key: B Question 10 of 12 4.0/ 4.0 Points Which of the following is the active ingredient of baking soda?  A.NaOH  B.NaHCO3  C.KOH  D.NH3  E.none of the above Answer Key: B

Part 3 of 3 - 10.0/ 10.0 Points Question 11 of 12 5.0/ 5.0 Points Define “indicator” using the knowledge from your lab. An indicator is a substance that undergoes a distinct observable change when conditions in its solution change. Examples: A pH indicator changes color over a narrow range of pH values in solution. The color of the solution changes depending on the pH of the solution Question 12 of 12 5.0/ 5.0 Points If a 10.00mL sample of unknown concentration of HF is titrated with 28.94mL of 0.1040M NaOH, what is the concentration of HF? Use the formula M1 * V1 = M2 * V2 Because multiplying Molarity and volume gives number of moles reacting.  We are looking for M1. 10.00ml * x = 28.94mL * 0.1040M 10.00ml * x = 3.009M x =0.3009M Concentration of HF = 0.3009 M Feedback: Found in Chapter 14 and relates to the lab

Question 1 of 12 4.0/ 4.0 Points You are preparing solutions in the lab and need to make 250.0 mL of a 2.00 M HCl solution. All you have in stock is 6.00 M HCl. How many milliliters of the stock solution do you need?  A.83.3 mL  B.750.0 mL  C.0.048 mL  D.520.0 mL Answer Key: A Feedback: Good. Question 2 of 12 4.0/ 4.0 Points What mass of sucrose, C12H22O11 is present in 75.0 mL of a 2.50 M solution?  A.642 grams  B.64.2 grams  C.0.188 grams  D.188 grams Answer Key: B Question 3 of 12 4.0/ 4.0 Points Which of the following is true of dissolving gases in water?  A.As pressure above the solution increases, solubility decreases.  B.As pressure above the solution increases, solubility increases.  C.It doesn't matter because gases don't dissolve in water.  D.Pressure above the solution has no influence on solubility. Answer Key: B Feedback: Good. Solubility of gases is in 13.4 Question 4 of 12 4.0/ 4.0 Points If you have 150.0g of solid sodium hydroxide and need to make a 1.50M solution, how many liters of solution can you make?  A.100.  B.0.01  C.250  D.2.50 Answer Key: D Feedback: Good. Molarity is discussed in 13.6 Question 5 of 12 4.0/ 4.0 Points If I start with 46 mL of 1.25 M HCl and dilute it to a volume of 250 mL, what is the concentration of my final solution?  A.0.23 M  B.5.8 M  C.0.18 M  D.6.8 M Answer Key: A Feedback: Good. Solution dilution is discussed in 13.7

Part 2 of 3 - 20.0/ 20.0 Points Question 6 of 12 4.0/ 4.0 Points According to Bronsted-Lowry, an acid:  A.is a proton acceptor.  B.produces H⁺ in solution.  C.produces OH⁻ in solution.  D.is a proton donor. Answer Key: D Feedback: Good. Definitions discussed in 14.4 Question 7 of 12 4.0/ 4.0 Points Which of the following compounds is a base that is used to make fertilizer?  A.sodium bicarbonate  B.potassium hydroxide  C.sodium hydroxide  D.ammonia  E.sodium phosphate Answer Key: D Feedback: Good. Base properties and examples are discussed in 14.3 Question 8 of 12 4.0/ 4.0 Points How could you describe an acid based on Arrhenius's theory?  A.produces OH⁻ in solution.  B.produces H⁺ in solution.  C.a proton acceptor.  D.a proton donor.  E.none of the above Answer Key: B Feedback: Good. These definitions are covered in 14.4 Question 9 of 12 4.0/ 4.0 Points Which of the following is true of alkaloid compounds?  A.Some narcotic drugs are alkaloids.  B.Alkaloids are organic bases.  C.Some alkaloids are addictive.  D.Alkaloids occur naturally in many plants.  E.All of the above were mentioned. Answer Key: E Feedback: Good. Alkaloids were discussed in 14.3 Question 10 of 12 4.0/ 4.0 Points Which of the following acids would be classified as diprotic?  A.HCl  B.HI  C.H2SO4  D.HClO4  E.HNO3 Answer Key: C Feedback: Good. Strong/weak acids are discussed in 14.7

Part 3 of 3 - 9.25/ 10.0 Points Question 11 of 12 4.75/ 5.0 Points Calculate the number of grams of sodium bicarbonate, NaHCO3 in each of the following solutions. You must show your work to receive credit. a) 25.0 mL of 0.975M  b) 1.30 L of 2.50 M c) 625 mL of 6.80 M d) 3.00 L of 0.025 M Number of moles = Molarity * Volume in litres a) 25.0 mL of 0.975M  n = 0.975 * 0.025 = 0.024375 moles  1 mole of NaHCO3 weighs 84 grams. As molar mass is 84 grams 0.024375 moles weighs  0.024375*84 = 2.0475 grams b) 1.30 L of 2.50 M n = 2.5 * 1.30 = 3.25 moles  1 mole of NaHCO3 weighs 84 grams. As molar mass is 84 grams 3.25 moles weighs  3.25*84 = 273 grams c) 625 mL of 6.80 M n = 6.80 * 0.625 = 4.25 moles  1 mole of NaHCO3 weighs 84 grams. As molar mass is 84 grams 4.25 moles weighs  4.25*84 = 1160.25 grams d) 3.00 L of 0.025 M n = 0.025 * 3 = 0.075 moles  1 mole of NaHCO3 weighs 84 grams. As molar mass is 84 grams 0.075 moles weighs  0.075*84 = 6.3 grams Comment: Good Job! Check your math on c. You did it correctly, but your final answer is incorrect. Question 12 of 12 4.5/ 5.0 Points Explain the difference between a strong and weak acid AND between a strong and weak base. Use terminology and concepts from this lesson and provide sufficient detail. Strong acids and bases completely ionizes in a solution. Weak acids and bases only only partially ionize in a solution. The strength of an acid or base is the degree of ionization in solution which in turn means the ability to give or accept protons. For example Acetic acid is week because only 1 in 10,000 acid molecules break up to give the H+ ion in solution. HCl is a strong acid because it completely dissociates into H+ and Cl- A weak base does not ionize fully in an aqueous solution. For example NaOH is a stronger base than diethylamine. Comment: You're on the right track!  Acids are molecular substances. Strong acids completely ionize in water, whereas weak acids do not. Generally, weak acids do not ionize well in water and do not produce H+ nearly as easily or frequently as strong acids.  Strong bases are bases that are fully ionic compounds, although some may not readily dissolve or ionize in water. Strong bases produce hydroxide ions in water, whereas weak bases do not. For example, ammonia does not produce hydroxide ions in water, but can act as a hydrogen acceptor and form ammonium, which in turn will form some hydroxide (not much). A weak base does not completely convert into hydroxide ions