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What is the Molar Mass of H2O? (Include Units)
18.016 g/mol
What is Avogadro's Number? (Include Units)
6.022 x 1023 atoms/mole
What is the unit of Molar Mass?
g/mol
How many Phosphorus's are in Phosphate? (Flashcard)
1 P
How many Chlorines are in Magnesium Chloride? (criss cross)
MgCl2 -- 2
How many moles are in 2.6 grams of Helium (He)? Include all work and units
2.6 / 4.003 = 0.60 moles He
How many moles are in 3.2 x 1023 atoms of silver? (include all work and units)
(3.2 x 1023 atoms Ag) / (6.022 x 1023 atoms Ag) = 0.50 moles of Ag
How many grams are in 0.41 moles of Oxygen (O)? (Include all work and units)
0.41 moles) * 16 grams O = 6.6 grams O
How many atoms are in 0.045 moles of Zinc? (include all work and units)
0.045 moles Zn * (6.022 * 1023 atoms Zn) = 2.7 * 1022 atoms Zn
How many grams are in 2.3 moles of Sodium (Na)? (include all work and unit)
2.3 moles Na * 22.99 grams Na = 52.9 (53 sig fig) grams of Na
What is the Molar Mass of NaCl? (Show all work and units)
22.99 + 35.45 = 58.4 g/mol NaCl
What is the Molar Mass of Li2(CO3)? (Show all work and units)
2(Li) + 1(C) + 3(O)
2(6.94) + (12.01) + 3(16.00) = 73.9 g/mol
What is the Molar Mass of CaBr2? (Show all work and Units)
1(Ca) + 2(Br)
40.08 + 2(79.90)
199.9 g/mol
How many grams are in 0.023 moles of Water? (Molar mass of water = 18.016 g/mol)
0.023 moles H2O * 18.016 g/mol = 0.414 grams H2O
What is the percent composition of all the elements in CO2 (Molar mass for CO2 = 44.01 g/mol)
C: (12.01/44.01) * 100 = 27.29% Carbon
O: (32/44.01) * 100 = 72.71% Oxygen
What is the Molar mass of Potassium Phosphate? (K3PO4) (include all work and units)
K3(PO4) = 3(K) + 1(P) + 4(O)
3(39.10) + (30.97) + 4(16) = 212.27 g/mol
How many grams are in 0.0065 moles of Lithium Sulfide? Molar Mass = 71.06 g/mol (Show all work and units)
Li2S = 6.94 + 2(32.06) = 71.06 g/mol
0.0065 moles Li2S * 71.06 g/mol Li2S = 0.46189 grams
0.46 grams Li2S
What is the percent composition of all elements in table salt NaCl? (show all work and units)
NaCl = 22.99 + 35.45 = 58.44
%Na = (22.99/58.44) * 100 = 39.34 % Na
%Cl = 100% - 39.34 = 60.66 % Cl
How many Moles are in 78.3 grams of Potassium Bromide? (Molar Mass = 119 g/mol) (Include all work and units AND SIG FIGS)
KBr = 39.10 + 79.90 = 119 g/mol KBr
78.3 grams KBr / 119 g/mol KBr = 0.65798 moles
0.658 moles KBr
What is the Molar Mass of Calcium Hydroxide (Use criss cross method and flashcards!) Show all work and units
Calcium Hydroxide = Ca(OH)2
MM = 1(Ca) + 2(O) + 2(H)
= 40.08 + 2(16) + 2(1.008)
= 74.096 g/mol
A compound is 23.3 g magnesium, 30.7 g sulfur, and 46.0 g oxygen. What is the Empirical Formula?
S: 30.7/32.06 = 0.9576 divide by lowest = 1
O: 46/16 = 2.875 divide by lowest = 3
Empirical = MgSO3 = 24.3 + 32.06 + 3(16) = 104.36
Molecular = (313.08/104.36) = 3 MULTIPLY
Mg3S3O9
How many atoms are in 230 grams of Calcium Hydroxide (MM = 74.096) (show all work and units)
230 grams Ca(OH)2 / MM =
3.104 moles Ca(OH)2 * (6.022 *1023 atoms) =
1.87e24 or 1.9 x 1024 atoms Ca(OH)2
A compound is 27.29 g Carbon and 72.71 g oxygen. What is the Empirical Formula? (show work)
C: 27.29 / 12.01 = 2.272 moles C
O: 72.71 / 16 = 4.544 moles O
DIVIDE BY LOWEST MOLES
C = 1
O = 2
CO2
How many atoms are in 6.1 * 103 grams of Calcium Chloride? (Molar Mass = 110.98 g/mol) (Show all work, units, AND SIG FIGS)
Grams --> Atoms
MM CaCl2 = 40.08 + 2(35.45) = 110.98 g/mol
(6.1 * 102 grams CaCl2) / MMCaCl2 = 5.496485 moles CaCl2
5.4964 moles CaCl2 * Avogadros Number = 3.30998 e24
3.3 * 1024 atoms CaCl2
How many Grams are in 8.2 * 1025 atoms of Calcium Chloride? (Molar Mass = 110.98 g/mol) (Show all work, units, AND SIG FIGS)
Atoms --> Grams
MM CaCl2 = 40.08 + 2(35.45) = 110.98 g/mol
(8.2 * 1025 atoms CaCl2) / Avogadro's number = 136.167 moles CaCl2
5.4964 moles CaCl2 * MMCaCl2 = 15111 grams
1.51 x 104 grams CaCl2