Molar Mass
How do you find the molar mass of an element?
The mass of one mole of an element is given on the periodic table in grams per mole.
How many moles are there in 87.62 grams of Sr?
(Include correct units. IGNORE sig. figs. for this one)
1 mole of Sr
*Molar Mass on PT = g/mol = grams per 1 mole
How many atoms of carbon are in 1 mole of carbon?
(Include correct units. IGNORE sig. figs. for this one)
6.02 x 1023 atoms of carbon
*Avogadro's Number = 6.02 x 1023 = 1 mole of any substance
How many grams are there in 6.02 x 1023 atoms of C?
(Include correct units. IGNORE sig. figs. for this one)
12.01 grams of C
(or 12.011 grams, depending on which PT you use)
*Avogadro's Number = 6.02 x 1023 = 1 mole of any substance
*Molar Mass on PT = g/mol = grams per 1 mole
Describe how the mass, in grams, of an element is converted to the number of moles.
(In words/complete sentences)
Divide the given mass, in grams, by the molar mass of the element, which is found on the PT.
What is the molar mass of one Sulfur atom?
(Include units. Answer in 2 sig. figs.)
32.06 g/mol
How many grams are there in 6.50 moles of copper?
(Include units and correct sig. figs.)
413 g Cu
How many atoms are there in 0.250 moles of S?
(Include units and correct sig. figs.)
1.51 x 1023 atoms of S
How many grams are there in 10.5 x 1023 atoms of Mg?
(Include units and correct sig. figs.)
42.4 grams Mg
(a) What is Avogadro's Number (in #'s)
(b) For conversions between what units do we use Avogadro's Number (In words/complete sentences)?
(a) Avogadro's Number = 6.02 x 1023
(b) We use Avogadro's Number when converting between moles and particles (atoms/molecules).
Describe how we determine the molar mass of a compound. (In words)
By adding together the masses of each element (which are found on the periodic table) that are present in the compound and accounting for how many of that element is present.
How many moles are there in 13.8 grams of NaCl?
(Include units and correct sig. figs.)
0.236 moles of NaCl
How many molecules of carbon dioxide (CO2) are in 2.00 moles of carbon dioxide?
(Include units and correct sig. figs.)
1.20 x 1024 molecules of carbon dioxide
How many molecules are in 6.755 grams of O2?
1.271 x 1023 molecules of O2
Describe how to convert the number of atoms to the number of moles.
(In words/complete sentences)
Divide the given number of atoms by Avogadro's Number, 6.02 x 1023.
What is the molar mass of O2?
(Include units and correct sig. figs.)
32.00 g/mol
What is the mass, in grams, of 3.000 moles of carbon disulfide, CS2?
(Include units and correct sig. figs.)
228.4 grams of carbon disulfide
How many moles are there in 3.011 x 1023 atoms of magnesium?
(Include units and correct sig. figs.)
0.5002 mol Mg
How many atoms are there in 305.04 grams of NaCl?
3.1421 x 1024 atoms of NaCl
Describe how to convert the mass, in grams, of an element to the number of atoms present.
(In words/complete sentences)
Divided the given mass, in grams, by the molar mass of the element (found on the PT), then multiply that by Avogadro's Number, 6.02 x 1023.
What is the mass of one mole of sugar (sucrose), if sugar has the chemical formula: C12H22O11
(Include units and correct sig. figs.)
342.29 g/mol
How many moles are there in 124.80 grams of sugar (sucrose), if sugar has the chemical formula: C12H22O11
(Include units and correct sig. figs.)
0.36460 moles of sugar (sucrose)
How many moles of caffeine (C8H10N4O2) are present in 7.23 x 1025 molecules of caffeine?
(Include units and correct sig. figs.)
120. moles of caffeine
How many grams of sugar (C12H22O11) are present in 9.871 x 1023 molecules of sugar?
(Include units and correct sig. figs.)
561.3 grams of sugar
How do you set up a unit conversion problem using conversion factors?
Set up a fake conversion equation, using "given" and "wanted" instead of real given values or conversion factors.
Your final answer should be an EQUATION.
*Use given/wanted in place of any unit or number to describe the correct unit placement.
Given x (Wanted/Given) = Wanted