The carat is the unit of mass used by jewelers. One carat is exactly 200mg. How many carbon atoms are present in a 1.5-carat diamond?
1.50 X 10^22 carbon atoms (0.0250 mol)
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5
Round 5: Find the molar mass of K2Cr2O7 and Fe2(SO4)3.
K2Cr2O7 = 294.2 g/mol
Fe2(SO4)3 = 399.91 g/mol
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15
2NaN3(s) --> 3N2(g) + 2Na(s)
To inflate the air bag on the driverâs side of the car, 80.0g of N2 is required. What mass of NaN3 is needed to produce 80.0g of N2?
124 g
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10
a reactant that is still present after a chemical reaction is complete
excess reagent
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20
Round 4: A sample of pure acetic acid CH3COOH contains 1.40 x 10^23 carbon atoms. How many moles of acetic acid are in the sample?
0.116 mol
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25
In one reaction, 0.507 mol of SiCl4 is produced. How many molecules of chlorine were used in the reaction?
6.10 X 10^23 molecules (1.014 moles)
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20
What is the mass percentage of carbon in C10H14O?
80.0%
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15
How many grams are in 1.54 mol of beryllium?
13.88 g
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15
Calculate the molar mass of calcium carbonate
100.09 g/mol (1X40.08 + 1X12.01 +3X16.00)
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15
How many grams are in 2.73 mol of lithium?
18.95 g
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20
A 26.2g sample of oxalic acid hydrate (H2C2O4 âĒ 2H2O) is heated in an oven until all the water is driven off. How much of the anhydrous salt is left?
18.7 g
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15
Mass of 0.82 mol of a diatomic molecule is 131.3 g Identify the molecule
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5
Round 1: Naturally occurring silver exists as two isotopes. From the table above, calculate the average atomic mass of silver.
