Avogadro's #
How many atoms of chlorine in 0.76 mol of Cl2?
(0.76) (2) (6.022 x 1023) =
9.2 x 1023 atoms of Cl
What is the volume of 0.6 mol of O2? (at STP, 1 mol = 22.4L)
(0.6) (22.4) = 13.44 L =
10 L
In the reaction __C2H6 + __O2 → __CO2 + __H2O, what is the mole ratio of O2 : H2O?
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
7:6
2Br + 3Ch + 9Cc → 1Sa
If I have 20 slices of bread, 50 slices of cheese, and 81 cold cuts, how many sandwiches can be made?
Cold cuts is limiting ingredient
81/9 = 9 sandwiches
What does “hasta luego” mean in Spanish?
“See you later”
How many atoms of hydrogen in 0.62 mol of CH3OH?
(0.62) (4) (6.022 x 1023) =
1.5 x 1024 atoms of carbon
What is the volume of 6.798 mol of N2 (at STP, 1 mol = 22.4 L)
(6.798) (22.4) =
152 L
If I have 603g of C6H12O6, how many moles of C6H12O6 do I have?
(603) / (180.18)
3.35 mol C6H12O6
3Mg(OH)₂ + 2H₃PO₄ → Mg₃(PO₄)₂ + 6H₂O
If 55.7 grams of Mg(OH)₂ reacts with 72.4 grams of H₃PO₄, which is the limiting reactant?
55.7 g / 58.33 g/mol = 0.9549 mol Mg(OH)₂
72.4 g / 97.99 g/mol = 0.7388 mol H₃PO₄
Mg(OH)₂ is the limiting reactant.
What does “xie xie” mean in Chinese?
“Thank you”
How many molecules of H2O are in 4.00g of H2O?
(4.00) (1 / 18.02) (6.022 x 1023) =
1.34 x 1023 molecules of H2O
If I have 300.2 L of H2, how many mols of H2 do I have? (at STP, 1 mol = 22.4 L)
(300.2) (1 / 22.4) =
13.4 mol H2
2Na + Cl2 → 2NaCl
If I have 2.00 mols Na and an excess of Cl2, how many grams of NaCl could I make?
(2) (2/2) (58.44) = 116.88
= 117g NaCl
If the theoretical yield is 64.79g of product, but in the experiment only 47g of the product is produced. What is the percent yield?
47 / 64.79 x 100% = 73% percent yield
When is the last day of school?
June 11
How many molecules of SO3 are in 605.7g of SO3?
(605.7) (1 / 80.07) (6.022 x 1023) =
4.555 x 1024 molecules of SO3
If I have 54.06g of water vapor, how many L of H2O do I have? (at STP, 1 mol = 22.4 L)
(54.06g) (1 / 18.02) (22.4) =
67.2 L
If I have 8.72 mols of Fe and an excess of O2, which synthesize into Fe2O3, how many grams of Fe2O3 do I make?
(8.72) (2 / 4) (159.69) =
696g Fe2O3
2Na + Cl2 → 2NaCl
If 2.00 mols of Na react with 3.00 mols of Cl2, how many grams will I have of the excess reactant?
2 mols Na reacts with 1 mol of Cl2
2 mols of Cl2 leftover
(2) (70.90) = 142g Cl2
Which element has the largest atomic radius?
Francium (Fr)
How many atoms of oxygen in 700g of NO3?
(700) (1 / 62.01) (3) (6.022 x 1023) =
2 x 1025 atoms of oxygen
If I have 22L of N2, how many grams of N2 do I have? (at STP, 1 mol = 22.4 L)
(22) (1 / 22.4) (28.02) =
28 L
Cu + 4HNO3 → Cu(NO3)2 + 2H2O + 2NO2
If I have 40.93g of HNO3 and an excess of Cu, how many grams of water will I make?
(40.93) (1 / 63.01) (2 / 4) (18.02) =
5.853g H2O
3Mg(OH)₂ + 2H₃PO₄ → Mg₃(PO₄)₂ + 6H₂O
If 4.00 mols of Mg(OH)₂ reacts with 5.00 mols of H₃PO₄, how many grams of H₂O are made?
(4) (6 / 3) (18.02) =
144 grams of H₂O are made
How many students do we have in this class?
P5: 29
P6: 33