What do I know about moles?

Transcription

1 What do I know about moles? What do I want to know about moles? What have I learned about moles today?

2 This unit test contains 6 types of problems: 1. must be able to write a chemical formula 2. Grams to moles (using ) 3. Moles to particles/atoms/molecule (using ) 4. Grams to moles to particles (using ) 5. formulas 6. formulas

3 The SI (metric) unit used to measure the 1 mole is always equal to: -- (g/mole) -- (6.02 x ) -- (AKA molar volume) These may be used as conversion factors when working mole problems.

4 Define molar mass AND Avogadro s number.

5 Ex: Titanium = g/mole (this sample contains of atoms) Ex: oxygen = g/mole (this sample contains of atoms)

6 Multiply from periodic table Ex:Magnesium hydroxide Mg (OH) 2 Mg= ( ) = O= ( ) = H= ( ) = g/mole (this mass also contains Avogadro s number of molecules)

7 Find the molar mass of aluminum sulfate

8 Calculate the molar mass of diarsenic trioxide.

9 1 mole of this substance table sugar (sucrose)-- C 12 H 22 O 11 Sodium chloride-- NaCl Cupric sulfate-- CuSO 4 # of atoms/ molecules/ particles Mass of 1 mole (molar mass) g/mole Sulfur--S 32.1 Volume of 1 mole Iron--Fe 55.8 Water H 2 O 18.0

10 Stannic carbonate Diarsenic pentasulfide Hydrofluoric acid

11 Sucrose

12 Shows the % of each element that makes up a compound Must be calculate first. Ex: magnesium hydroxide Mg (OH) 2 Mg 1 x 24.3 =24.3 O 2 x 16= 32.0 H 2 x1.0 = g/mole

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14 Calculate the % composition of sulfurous acid

15 SAVE YOUR WRAPPER FOR ENTIRE LAB!! DO NOT START CHEWING UNTIL YOU SIT DOWN BACK AT YOUR DESK. CHECK BALANCE TO MAKE SURE IT S OK BEFORE YOU START!!

16 READ PROBLEM: MAKE A HYOTHESIS: PROCEDURE 1 4 DATA TABLE 1 5

17 After chewing: (KEEP YOUR SAME BALANCE) Procedure 5 8 Data table 6 8 Conclusion Questions 1 2

18 Calculate the % composition for a sugar substitute called SUCRALOSE

19 1. Calculate the % composition of carbonic acid. 2. Calculate the % composition of diantimony trioxide.

20 Calculate the molar mass AND % composition of: 1. C 12 H 22 O Cupric sulfate

21 Will need to use unit conversion(cancellation) and will be used for the conversion factor. Ex: 2.50 grams of hydrochloric acid = moles

22 Ex: 2.50 moles of HCl = grams

23 (synonyms) Will have to use as a conversion factor Ex: 5.25 x atoms of Mg = moles

24 2.50 moles MgO = molecules

25 Will need to use both AND as conversion factors Will be 2 steps instead of 1 step unit cancellation Ex: 4.5 grams nitrous acid = molecules

26 Ex: 9.35 x particles of carbon tetrabromide = grams

27 If grams are converted to moles, use to convert. If moles are converted to molecules, then use to convert. ****Have calculator, periodic table, and best friend chart****

28 All members of your group must show their work on separate sheet of paper. When you calculate the answer, flip the card over to find a word. All of your words will make a sentence. First group to show all work and finish first, wins bonus!

29 grams of sodium oxide = moles x particles of sodium= moles x atoms of acetic acid = grams

30 Video sheet Problems #1 3, 5, 6

31 Fill in the blanks with multiply/divide OR molar mass/avogadro s number: ***When going from moles to grams, by. ***When going from moles to particles, by. I AM CHECKING 5 HOMEWORK PROBLEMS!!!!

32 Briefly describe the steps for calculating an empirical formula AND molecular formula.

33 Define empirical formula ***both labs due today***

34 1. Convert 5.03 x molecules of phosphoric acid to grams. 2. Convert grams of dinitrogen monoxide to moles. 3. Convert 5.0 moles of water to molecules.

35 Tell how to solve for each: 1. G to moles 2. Moles to G 3. Particles to moles 4. Moles to particles 5. G to particles 6. Particles to G

36 HYPOTHESIS, DATA 1 8, CONCLUSION, QUESTIONS MASS OF SUGAR (in grams data #8) MOLES (SUGAR = C 12 H 22 O 11 ) 4. MOLES PARTICLES

37 Data Table: mass of empty vial AND substances mass (make sure you ve subtracted empty vial each time!!) SHOW WORK TO GET CREDIT CONVERT GRAMS MOLES CONVERT MOLES PARTICLES ANSWER QUESTIONS 1---5, 6 (BONUS)

38 Convert 25.0 moles of water to grams.

39 A molecular formula is a whole number of the empirical formula.

40 Shows the ratio of elements in a compound Will give you of compound and ask you to find the formulas

41 1. Change to (some problems may already give you grams instead of %) 2. Convert (using molar mass) **round to *** 3. Simplify the mole ratio by 4. Round to the nearest number and these numbers to the appropriate element

42 A compound is 78.1% Boron and 21.9% H. Calculate the empirical formula.

43 Is a of the empirical formula You must then first know the formula

44 1. You must first have formula (if not, you will have to first!!) 2. Find the of the formula. 3. Take the molar mass of the molecular formula that is given in the problem by the empirical formula s molar mass. Round this to a number. 4. this number to the numbers within the empirical formula to get the new molecular formula.

45 Given the empirical formula of BH 3 and the molecular formula s molar mass of g/mole, find the molecular formula.

46 A compound is 4.04 grams of nitrogen and grams of oxygen. The molecular molar mass is g/mole. Find the molecular formula.