Units & Sig Figs
Avogadro's Number is measured in what general unit?
Representative particles
What number is Avogadro's Number reported as?
6.02 x 1023
What is the molar mass of Ca?
40.078 g/mol Ca
What is the name of the conversion factor that describes the relationship between the numbers of moles of any two of the substances in a balanced chemical equation?
Mole Ratio
The amount of product formed in a chemical reaction depends on the _________ _________.
limiting reactant
What is the unit for molar mass?
g/mol
How many atoms are in 4.5 moles of C?
2.7 x 1024 atoms C
What is the molar mass of LiNO3?
68.944 g/mol LiNO3
Write the balanced chemical equation for the following reaction: iron reacts with oxygen to form iron (III) oxide.
4 Fe + 3 O2 --> 2 Fe2O3
True or False: The theoretical yield is the amount of product actually formed in a chemical reaction in a lab or experiment.
False
How many significant figures are in the number, 0.300?
3
How many moles are in 6.83 x 1022 atoms of Na?
0.113 mol Na
What is the mass, in grams, of 1.25 mol Al?
33.7 g Al
What is the mole ratio between KClO3 and O2 from the following chemical reaction?
2 KClO3 --> 2 KCl + 3 O2
2 mol KClO3 / 3 mol O2
OR
3 mol O2 / 2 mol KClO3
50.0 g of Mg and 75.0 g of HCl react to form MgCl2 and H2. What is the limiting reactant?
Mg + 2 HCl --> MgCl2 + H2
HCl is the limiting reactant
How many significant figures are in the number 560?
2
How many molecules are in 7.44 mol of CO2?
4.48 x 1024 molecules CO2
How many moles are in 214 g of CaF2?
2.74 mol CaF2
How many moles of oxygen are necessary to react completely with 3.4 moles of propane (C3H8)?
C3H8 + 5 O2 --> 3 CO2 + 4 H2O
17 mol O2
Determine the theoretical yield, in grams, of Al2O3 when 43.4 g of Al reacts with O2.
4 Al + 3 O2 --> 2 Al2O3
82.0 g Al2O3
How many significant figures are in the number 25.00?
4
How many moles are in 3.125 x 1026 formula units of KCl?
519 mol KCl
How many formula units are in 89.3 g MgSO4?
4.47 x 1023 formula units MgSO4
What mass of N2 is produced from the decomposition of 102 g NaN3?
2 NaN3 --> 2 Na + 3 N2
65.9 g N2
Calculate the percent yield of S2Cl2 if the theoretical yield is 98.3 g S2Cl2 and a student recovered 96.4 g S2Cl2 in the lab.
98.1% S2Cl2