Unit 4 Quiz 2 – Moles and Formulas

The Review!

(you need a periodic table, piece of scrap paper, and calculator)

Review Game Rules

• I will ask a question to the class.• Each participant (that’s you) writes down the

answer silently.– Not each group…each individual.

• After a few moments, I will say, “Compare answers.”

• Each of you will look at what the other wrote.

Review Game Rules

• Did you each get the right answer?– 2 points.

• Did one of you get the right answer?– 1 point.

• Neither of you?– For shame. 0 points.– And eternal guilt.

Review Game Rules

• The List of Do Nots:– Do not talk to each other, make noises, gesture,

give answers (my discretion here) between when the question has been read and when I say, “Compare answers.”• Doing so will result in a disqualification for that round.

Don’t believe me? Try it.

– Do not fall asleep when I’m getting scores.• If you’re not paying attention, I’m not giving you points.

Review Question 1

• How many representative particles are in a mole of grilled cheese sandwiches?• 6.02 x 1023 grilled cheese sandwiches.

Review Question 2

• What’s the official name for 6.02 x 1023?– Avogadro’s Number.

Review Question 3

• If you have a mole of osmium (Os), you have 6.02 x 1023 what?– Atoms.

Review Question 4

• If you have a mole of water (H2O), you have 6.02 x 1023 what?– Molecules.

Review Question 5

• If you have a mole of diphosphorus pentoxide (P2O5), you have 6.02 x 1023 what?– Molecules.

Review Question 6

• If you have a mole of sodium oxide (Na2O), you have 6.02 x 1023 what?– Formula units.

Review Question 7

• What’s the formula for ammonium nitrate?– NH4NO3

Review Question 8

• What the name for Pb3(PO4)4?– Lead (IV) phosphate.

Review Question 9

• How many liters does a mole of H2O (g) take up? Assume standard temperature and pressure (STP).• 22.4 L.

Review Question 10

• How many liters does a mole of H2O (l) take up? Assume standard temperature and pressure (STP).– Cannot determine directly.– HOWEVER, give your team 3 bonus points if you

said that a mole of H2O is 18.0148 g, which, given water’s density, is 18.0148 mL, which is 0.0180148 L.

Review Question 11

• How many liters does a mole of Fr (s) take up? Assume standard temperature and pressure (STP).– Cannot determine directly.

Review Question 12

• BONUS NON-CHEMISTRY QUESTION• You may wager any/all of your points.• Category: Aviation History

• In May of 1927, Charles Lindbergh became the first to fly solo across the Atlantic. What was the name of his airplane?– The Spirit of St. Louis

Review Question 13

• BONUS NON-CHEMISTRY QUESTION• You may wager any/all of your points.• Category: Board Games

• Chess has its origins in a game called chaturanga. Which country first started playing chaturanga?– India.

Review Question 14

• Suppose you’re asked to convert grams to molecules. To what do you convert grams first?– Moles.

Review Question 15

• Assuming you actually are converting a quantity of grams to moles, what do you do to get moles?– Divide by the molar mass.

Review Question 16

• About how many moles are in 88.0 grams of carbon dioxide (g)?– About 2 (or 1.99) moles.

Review Question 17

• Now that you have a mole quantity, how do you get to molecules?– Multiply by Avogadro’s Number (6.02 x 1023).

Review Question 18

• And if you have 1.99 mol CO2, how many molecules is that?• 1.198 x 1024 molecules CO2.

Review Question 19

• But if you had 1.99 mol CO instead, how many molecules would that be?• 1.198 x 1024 molecules CO.

Review Question 20

• And how much space would that 1.99 mol CO take up?• 44.576 L.

Review Question 21

• BONUS NON-CHEMISTRY QUESTION• You may wager any/all of your points.• Category: Presidential Quantities

• In the Gettysburg Address, President Lincoln addressed the crowd first by saying, “Four score and seven years ago…”. How many is a score?– 20. The speech was given in 1863; he was referring

to 1776 – 87 years prior.

Review Question 22

• How are ionic compounds written – as empirical formulas, molecular formulas, or both?– Empirical formulas.

Review Question 23

• Any hydrate problem requires you to find two quantities in moles. What are those two quantities?– Moles of water evaporated.– Moles of anhydrous salt.

Review Question 24

• Once you find those two quantities (mol H2O, mol [salt]), what do you do with them?– Divide mol H2O by mol [salt].

Review Question 25

• Are hydrate formulas always written empirically or molecularly?– Empirically.

Review Question 26

• When finding an empirical formula, what’s the next step after converting masses to moles?– Divide each mol quantity by the smallest mol

quantity (then multiple to get rid of decimals if necessary).

Review Question 27

• Suppose you find an empirical formula to be CH2O. If the molecular formula is 90 g/mol, what’s the molecular formula?– C3H6O3.

Review Question 28

• Suppose you find an empirical formula to be CH4. If the molecular formula is 16 g/mol, what’s the molecular formula?– CH4.

Review Question 29

• For a hydrate formula, what would be the appropriate inequality?

• Moles of Water ____ Moles of Anhydrous SaltA. <B. ≤C. =D. >E. ≥– Choice E (≥).

Review Question 30

• BONUS NON-CHEMISTRY QUESTION• You may wager any/all of your points.• Category: Aviation History

• Capt. Paul Tibbets was partially responsible for killing or injuring 135,000 people. Who was he?– The captain of the Enola Gay, the aircraft that

dropped the atomic bomb on Hiroshima in 1945.