Chemistry I Accelerated Study Guideline - Chapter Ten The Mole

Transcription

1 Chemistry I Accelerated Study Guideline - Chapter Ten The Mole By the end of this chapter the skills you should be able to demonstrate are: 1. Name the basic SI unit for measuring the amount of a substance. 2. Distinguish between the terms gram atomic mass, gram molecular mass, and gram formula mass. 3. Define the relationship between the gram formula mass and the molar mass of a substance. 4. Explain the centrality of the mole to chemical calculations. 5. Convert using the mole between mass, number of particles, molarity and volumes of gas at STP. 6. Calculate the percent composition of a substance from its chemical formula or experimental data. 7. Derive the empirical formula of a compound from experimental data. 8. Derive the molecular formula of a compound from experimental data. 9. Determine the formulas of hydrates. Suggested Problems: p #76, 77, 80, 81, 83, 87, 88, 89, 90, 92, 93

2 Video Worksheet: The Mole Please Answer the following questions while you watch the video 1. What is the most basic kind of matter? 2. What is the motto of the same number trucking company? 3. What type of substance behaves as if its particles do not touch? 4. What are conditions must exist in order so a container can hold the same number of gas particles? 5. What does the Law of Combining Volumes state? 6. What is Avogadro s hypothesis? 7. What did Avogadro say about gas particles? 8. What is Relative Molecular Mass? 9. For many years, what served as the standard for relative molecular mass? 10. What is the modern machine that can determine the relative atomic mass of elements? 11. What is an isotope of an atom? 12. What is the standard today for relative atomic mass? 13. What is the volume of a mole of gas particles at standard temperature and pressure? 14. What is Avogadro s number in scientific notation? page 2

3 Basic Mole Problems Calculate the number of moles in each of these X atoms of lithium 6.02 X atoms Li X 1 mole Li = 1.00 mole Li 6.02 X atoms Li X molecules of nitrogen X molecules N 2 X 1 mole N 2 = moles N X molecules N X molecules of hydrogen peroxide X 10 5 formula units of potassium chloride X molecules of beryllium oxide X molecules of aluminum phosphide X molecules of carbon dioxide X molecules of Lead(II) iodide X molecules of bromine molecules of methane Calculate the number of atoms in each of these mole of gold 1.00 mole Au X 6.02 X atoms Au = 6.02 X atoms Au 1 mole Au moles of lead page 3

4 moles of ethanol moles of sodium bromide moles of zinc chloride moles of potassium nitrate moles of sodium phosphate mole of Tin(IV) fluoride moles of oxygen moles of carbon dioxide Calculate the molar mass of each of these 1. Silver chloride 2. Sodium hydroxide 3. Propane 4. Octane 5. Benzene 6. Copper(II) sulfate 7. methylamine (CH 3 NH 2 ) 8. Ethandiol (C 2 H 6 O 2 ) 9. Chloroform (CHCl 3 ) 10. Tribromosilane (SiHBr 3 ) 11. Sulfurous Acid 12. Ammonium phosphide page 4

5 Calculate the number of grams in each of these mole of Boron 1.00 mole B X 10.8 g B = 10.8 g B 1 mole B moles of Copper 2.00 mole Cu X 63.5 g Cu = 127 g Cu 1 mole Cu moles of Neon moles of Sodium Fluoride mole of glucose moles of nitrogen moles of magnesium oxide moles of calcium chloride moles of aluminum sulfide moles of water Calculate the number of moles in each of these g of carbon 12.0 g C X 1 mole C = 1.00 mole C 12 g C g of lithium oxide g of magnesium sulfide 89.4 g Li 2 O X 1 mole Li 2 O = 3.00 moles Li 2 O 29.8 g Li 2 O page 5

6 g of potassium phosphide g of sulfur dioxide g of calcium fluoride g of copper(ii) bromide g of diboron trioxide g of aluminum flouride g of sodium chloride Convert each of these to moles x molecules of carbon dioxide x molecules of chlorine x molecules of water molecules of tetraphosphorus decoxide molecule of ammonia grams of ammonia grams of calcium carbonate grams of water 8. page 6

7 grams of sulfuric acid gram of sodium chloride grams of lead(ii) sulfate grams of pentane grams of C 4 H 8 O grams of potassium permanganate x formula units of barium nitrate x formula units of magnesium bromide x molecules of ethane 17. Convert each of these to mass in grams moles of ammonia moles of sodium chloride moles of hydrochloric acid moles of sodium sulfate x 10 4 moles of silver chloride moles of calcium chloride moles of hydrofluoric acid 24. page 7

8 moles of silicon dioxide moles of nitrogen 26. Convert each of these to numbers of atoms moles of sulfur moles of silver moles of carbon dioxide moles of phosphorous trichloride moles of ammonia moles of sulfur dioxide x 10 3 moles of carbon monoxide moles of selenium moles of oxygen moles of silver nitrate moles of sodium fluoride 37. One step volume problems 38. How many moles are in 893 L of air at STP? What is the volume of moles of nitrogen gas at STP? How many moles of oxygen gas are in 694 L at STP? 40. page 8

9 41. What is the volume of 13.8 moles of carbon monoxide gas at STP? How many moles of neon gas are in 3.68 L at STP? What is the volume of moles of hydrosulfuric acid gas at STP? How many moles of argon gas are in 101 L at STP? What is the volume of 138 moles of hydrobromic acid gas at STP? 45. Two step mole problems 46. How many formula units are in 3.5 grams of sodium hydroxide? How many grams are in 6.10 x molecules of ethane? How many formula units are in 5.1 grams of titanium(iv) oxide? What is the mass of 3.62 x molecules of methanol? How many formula units are in 1.47 grams of lead(ii) chloride? What is the mass of 2.94 x molecules of decane? 51. page 9

10 52. How many formula units are in 5.62 grams of hydrosulfuric acid? How many atoms are in a tank that has 5.00 mol of nitrogen dioxide gas? How many formula units are in 3.00 grams of sodium chloride? How many molecules are in 30.6 grams of butanol? How many atoms are in L of helium at STP? If 12.1 grams of dry ice (carbon dioxide) are converted into gas at STP, what volume would it fill? 57. Molarity 1. What mass of potassium phosphate is needed to prepare 4.00 liters of 1.50 M solution? What mass of 2-pentanol is needed to prepare 1.50 liters of 3.00 M solution? 2. page 10

11 3. What volume in µl of 1.40 M acetic acid solution can be prepared using moles of acetic acid? What is the molarity of a solution that contains 85.0 grams of sodium sulfate in 325 ml of solution? What is the molarity of a solution that contains 215 grams of aluminum sulfate in 2.75 cubic decimeters of solution? What volume in µl of M solution can be prepared using 18.5 grams of sodium hydroxide? What is the molarity of a solution that contains 125 grams of ethanol in cubic decimeters of solution? What volume of M solution can be prepared using 90.0 grams of ammonium chloride? What is the molarity of a solution that contains 145 grams of sodium chloride in 275 ml of solution? How many grams of potassium chloride are needed to prepare L of a 1.50 M solution? 10. page 11

12 11. What is the molarity of a solution that contains 85.6 grams of hydrochloric acid in dm 3 of solution? How many grams of sodium hydroxide are needed to prepare 3.00 dm 3 of a 1.90 M solution? What is the molarity of a solution that contains 8.77 grams of potassium iodide in 4.75 dm 3 of solution? How many grams of iron(iii) chloride are needed to prepare 2.00 L of a 3.00 M solution? What is the molarity of a solution that contains 14.1 grams of ammonia in dm 3 of solution? How many grams of potassium hydroxide are needed to prepare 10.5 L of a 2.50 M solution? 16. page 12

13 Percent composition 1. Find the percent composition of a compound that contains 1.94 g of carbon, g of hydrogen and 2.58 g of sulfur in a 5.00-g sample of the compound 2. A sample of an unknown compound with a mass of g has percent fluorine and percent iron. If the compound is decomposed, how much of each element will be recovered? 3. Find the percent composition of a compound that contains 2.63 g of carbon, g of hydrogen and g of oxygen. 4. A sample of an unknown compound with a mass of g has percent carbon, 6.71 percent hydrogen, 4.06 percent nitrogen and percent oxygen. What is the mass of each element in this compound? 5. Find the percent composition of a compound that contains g of chlorine, g of oxygen and g of phosphorus. 6. Find the percent composition of a compound that contains 1.51 g of chromium, 1.13 g of potassium and 1.62 g of oxygen. 7. A sample of a compound with a mass of g is analyzed. The sample is found to contain only fluorine and oxygen. If the compound contains g oxygen, calculate the percent composition of the compound. page 13

14 Empirical Formulas 1. Determine the empirical formula of a compound containing g of gold and g chlorine. 2. Determine the empirical formula of a compound containing g of gallium and g phosphorus. 3. Determine the empirical formula of a compound containing 47.9% zinc and 52.1% chlorine by mass. 4. Determine the empirical formula of a compound containing 1.75 g of carbon and g bromine. 5. Determine the empirical formula of a compound containing 20.23% aluminum and 79.77% chlorine by mass. page 14

15 6. Determine the empirical formula of a compound containing g of carbon and g oxygen. 7. Determine the empirical formula of a compound containing g of calcium and g chlorine. 8. Determine the empirical formula of a compound containing g of carbon, g of hydrogen and g oxygen. 9. Determine the empirical formula of a compound containing 24.74% potassium, 34.76% manganese and 40.50% oxygen by mass. 10. Determine the empirical formula of a compound containing 2.16 g of aluminum, 3.85 g of sulfur and 7.68 g oxygen. page 15

16 Molecular Formulas 1. Determine the molecular formula of a compound containing g of palladium and 0.80 g of hydrogen. The molar mass of the compound is g/mol. 2. Determine the molecular formula of a compound that is 30.45% nitrogen and 69.55% oxygen. The molar mass of the compound is 92 g/mol. 3. Determine the molecular formula of a compound containing 42.4 g of hydrogen and g of carbon. The molar mass of the compound is 30.0 g/mol. page 16

17 4. Determine the molecular formula of a compound containing only boron and iodine if in a g sample, the mass of the iodine is found to be g. The molar mass of the compound is g/mol. 5. Determine the molecular formula of a compound containing g of oxygen and g of phosphorus. The molar mass of the compound is g/mol. page 17

18 Hydrates 1. Find the empirical formula of the hydrate given that it is 27.76% manganese, 35.83% chlorine and 36.40% water. 2. Two hydrates of cobalt(ii) chloride exist. One is 21.68% water the other is 45.43% water. What are their empirical formulas? page 18

19 Challenge Problems The Mole 1. How many molecules are in a sample of water that requires 8.40 kcal of heat energy to raise the temperature by 34.0 C? 2. A compound of hydrogen and carbon has a molar mass 114 g/mol. If one mole of the compound contains g of hydrogen, what is the compound s molecular formula? 3. How many atoms of iron are in a cube of iron that is 1.00 x 10 5 µm on a side? Use a reference source to find the density of iron. page 19

20 4. A mixture of salt and pepper analyses to be 50% chlorine by mass. If pepper contains no chlorine, what percent of the mixture is pepper? 5. A solution is made that is 2.00 M for aluminum nitrate. What volume of this solution contains moles of nitrate ions? page 20

21 6. A solution of ammonium sulfate is made that is 2.25 M for ammonium ions. What volume of this solution can be produced using only 50.0 g of ammonium sulfate? 7. A sample of hydrated sodium salt gives off 2.02 x molec. of water when it is heated. When the dehydrated sample is analyzed it is found to contain g sodium, g phosphorus, L hydrogen gas and 1.25 L of oxygen gas at STP. Calculate the empirical formula of the hydrate. page 21

22 Mole Word Scramble Use the clues provided to help you unscramble the letter to form words related to the mole. The letters in the circle spell out, in order, the name of a famous chemist. CLUES 1. 1/12 of a Carbon-12 atom 2. Mass of one object compared to that of another object x of anything 4. Method for solving a problem 5. Found by adding the atomic masses of all the elements in the molecule 6. Means that there are two atoms in a molecule 7. Formula representing the smallest whole-number ratio of atoms in a compound 8. Number of moles of dissolved substance per liter of solution 1. S A N I O M S M T T U A C I 2. V E T S A M S I R E L A 3. L O E M 4. M A H L T G I O R 5. R A L S U C E S A M L O M 6. T A D I M O C I 7. I M P E C I L A R 8. R I L Y T A O M NAME: page 22