Choose Your CategoryThe Final Question

The MoleAverage Atomic Mass and Molar MassFormulasPercentage CompositionLimiting ReactantsPercentage Yield and ErrorVocab100100100100100100100200200200200200200200300300300300300300300400400400400400400400500500500500500500500

The Mole - 100The SI base unit used to measure the amount of a substance whose number of particles equals the number of atoms of carbon in exactly 12 grams of carbon-12

BackThe Answer is the mole

The Mole - 200The number of atoms in a mole of any pure substance is called

BackThe Answer is the Avogadro's number

The Mole - 300What can be said about the atoms in 1 mol Ag and 1 mol Au?

BackThe Answer is they contain the same number of atoms.

The Mole - 400The _______________ in a chemical equation represent the relative number of moles of reactants and products.

BackThe Answer is coefficients.

The Mole - 500In the reaction N2 + 3H2 2NH3, what is the mole ratio of nitrogen to ammonia?

BackThe Answer is 1 to 2

Average Atomic Mass and Molar Mass - 100Using a periodic table, what is the average atomic mass of zinc?

BackThe Answer is 65.4 amu.

Average Atomic Mass and Molar Mass - 200What is 120 g/mol in amu?BackThe Answer is 120 amu.

Average Atomic Mass and Molar Mass - 300The atomic mass of hydrogen is 1.008 amu.This is because there is more than one ____________ of hydrogen.BackThe Answer is isotope.

Random Points600 points

Average Atomic Mass and Molar Mass - 400Calculate the molar mass of barium nitrate, Ba(NO3)2.

BackThe Answer is 261.35 g/mol.

Average Atomic Mass and Molar Mass - 500Change 58 grams of water into moles.BackThe Answer is 3.22 moles.(58g x 1mol/18 g)

Formulas - 100A formula that shows the simplest whole-number ratio of the atoms in a compound is the ________________ ___________.

BackThe Answer is empirical formula.

Formulas - 200The first step in finding the empirical formula from the percentage composition is to assume that you have this many grams?

BackThe Answer is 100 g.

Formulas - 300A compounds empirical formula is NO2. If the formula mass is 92 amu, what is the molecular formula?

BackThe Answer is N2O4

Random Points500 points

Formulas - 400A compound contain 79.85% carbon and 20.15 % hydrogen. What is the empirical formula?

BackThe Answer is CH3

Formulas - 500A compound contains 9.1 % hydrogen, 54.5 % carbon and 36.4 % oxygen. What is the molecular formula if its molar mass is132 amu?

BackThe Answer is H12C6O3

Percentage Composition 100The percentage of sulfur in SO2 is about 50%. What is the percentage of oxygen in this compound?

BackThe Answer is 50%.

Percentage Composition 200Calculate the percentage of sulfur in CuSO4.

BackThe Answer is 20.09%.

Random Points300 points

Percentage Composition 300What is the percentage composition of each element in CuCl2?

BackThe Answer is 47.3% Cu, 52.7% Cl.

Percentage Composition 400What is the percentage composition of CF4?

BackThe Answer is 13.6% C, 86.4% F

Daily Double

Percentage Composition 500What is the percentage composition of each element in (NH4)2HPO4?

BackThe Answer is 21.2% N, 6.8 % H, 23.5% P, and 48.5% O

Limiting Reactants - 100To determine the limiting reactant in a chemical reaction, one must change each reactant into the ________ product with the ________ units.

BackThe Answer is same (and same).

Limiting Reactants - 200A chemical reaction involving substances A and B stops when B is completely used. B is the ___________________.BackThe Answer is limiting reactant

Limiting Reactants - 300All the other reactants besides the limiting reactant are called ____________ reactants

BackThe Answer is excess.

Limiting Reactants - 400The first step in most stoichiometry problems is to _____________.

BackThe Answer is convert given quantities to moles.

Random Points800 points

Limiting Reactants - 500If 2 moles of each reactant are available for the reaction described by the following equation, SiO2(s) + 3C(s) SiC(s) + 2CO(g), determine which substance is the limiting reactant by calculating the moles of SiC each of the reactants can produced.BackThe Answer is carbon.

Percentage Yield and Error - 100

BackThe Answer is percentage yieldWhat is the ratio of the actual yield to the theoretical yield, multiplied by 100%?

Percentage Yield and Error - 200Actual yield must be determined by __________________.

BackThe Answer is experiments.

Random Points400 points

Percentage Yield and Error - 300For the reaction CH4(g) + 2O2(g) CO2(g) + 2H2O(g), calculate the percentage yield of carbon dioxide if 1000 g of methane (needed to calculate theoretical) react with excess oxygen to produce 2300g of carbon dioxide (experimental) .

BackThe Answer is 83.9%.

Percentage Yield and Error - 400What is the percent of error in evaluating the molecular mass of a compound if the experimental value was 69.2 amu and the known value was 75.5 amu?BackThe Answer is 8.3%

Random Points400 points

Percentage Yield and Error - 500For the reaction CH4(g) + 2O2(g) CO2(g) + 2H2O(g), calculate the percentage error of carbon dioxide if 1000 g of methane (needed to calculate theoretical) react with excess oxygen to produce 2300g of carbon dioxide (experimental).BackThe Answer is 16.1%

Vocab - 100The proportional relationship between two or more substances during a chemical reaction

BackThe Answer is stoichiometry

Vocab - 200The mass in grams of 1 mol of a substance

BackThe Answer is the molar mass

Vocab - 300The percentage by mass of each element in a compound

BackThe Answer is the percentage composition

Vocab - 400The measured amount of a product of a reaction

BackThe Answer is actual yield

Vocab - 500A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms

BackThe Answer is the molecular formula

The Final QuestionThe final question has to deal with:

StoichiometryMake your wager and hand it to the teacher

StoichiometryHow many molecules of hydrogen are produced if 20.0 g of sodium metal react with excess water according to the chemical equation: 2 Na(s) + 2 H2O(l) 2 NaOH(aq) + H2(g)?

And the Answer is:The Answer is 2.62 x 102320.0 x (1 mol/23 g) = 0.87 mol Na x (1 mol H2/2 mol Na) = 0.435 mol H2 x (6.02x1023 molecules/1 mol) =