Smeagol
Frodo
Gandalf
Aragorn
Sauron
100
What is the definition of an empirical formula?
A simplified, base version of the molecular compound.
100
Daily Triple
What is percent composition?
The mass of the element divided by the mass of the total compound multiplied by 100%.
100
Daily Triple
What does STP stand for?Standard-Temperature-Pressure
100
Daily Double
What is Avogadro's Law for gases?
1 mol of any gas will equal 22.4 L of that gas at STP.
100
What is molar mass?
The amount of mass, in grams, of an element in one mole of that substance.
200
What is a representative particle?
An atom or a molecule.
200
Daily Double
What is Avogadro's Number?
6.022 x 1023
200
What is a molecular formula?
The multiple formula of te empirical formula.
200
How would you, in your own words, define the word, mole?
The amount of a substance.
200
Daily Double
What is the mole roadmap and what is it used for?
It is used to navigate between conversions involving, mass, volume, and representative particles.
300
What allows you to convert between the mass and the number of moles of a substance?
Molar Mass
300
Daily Double
How do you use Avogadro's law to relate the volume of a gas at STP and the number of moles of the gas?
Use the molar volume of 22.4 L, which equals 1 mol at STP.
300
Three balloons filled with three different gaseous compounds each have a volume of 22.4 L at STP. Do these balloons have the same mass or contain the same number of molecules? Explain.
They contain the same number of molecules; however, the masses can differ depending on the molar masses of the substances.
300
Daily Double
A chemist collects 2.94 L of carbon monoxide (CO) gas at STP during an experiment. How can she can determine the mass of gas that she collected?
Divide 2.94 L by 22.4 L/mol, and then multiply by the molar mass of carbon monoxide
300
How do chemists count the number of representative particles in a substance?
They use the mole.
400
Daily Double
What equals the molar mass of an element?
The atomic mass of the element expressed in grams
400
What equals the molar mass of a compound?
The sum of the masses of elements in one mole of the compound
400
Daily Triple
Calculate the percent composition of calcium acetate, Ca(C2H3O2)2.
25.4% Ca; 30.4% C; 3.8% H; 40.5% O
400
How is the molecular formula of a compound related to its empirical formula?
They could be the same, or the molecular formula could be a whole-number multiple of the empirical formula.
400
What information can you use to calculate the empirical formula of a compound?
The percent composition of the compound.
500
How do you calculate the percent composition of an element in a compound?
Divide the mass of an element in the compound by the mass of the compound, and multiply by 100%.
500
Daily Double
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500
How many moles is 1.50 × 1023 molecules of NH3?
0.249 mol NH3
500
Calculate the percent composition of the compound that forms when 222.6 g N combines completely with 77.4 g O.
74.2% N; 25.8% O
500
Daily Double
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