Chemical Aspects Quiz

What is stoichiometry?

• Stoichiometry is the calculation of reactants and products in chemical reactions based on the law of conservation of mass.

• Stoichiometry is the art of painting using only primary colors.

• Stoichiometry is the process of extracting minerals from the earth's crust.

• Stoichiometry is the study of stars and galaxies.

How do you calculate the limiting reactant in a chemical reaction?

• Count the number of products formed

• Use the reactant with the highest molar mass

• Calculate the moles of each reactant and compare to find the limiting reactant.

• Select the reactant with the lowest density

What is the empirical formula of a compound if it consists of 40% carbon, 6.7% hydrogen, and 53.3% oxygen?

• C2H4O2

• C3H6O3

• C2H5O2

• CHO

How do you determine the percentage purity of a substance?

• Total sample amount / Desired substance amount * 100

• Total amount of sample / Actual amount of desired substance * 100

• Actual amount of desired substance / Total amount of sample * 100

• Desired substance amount / Total sample amount * 100

Calculate the molecular formula of a compound with an empirical formula of CH2O and a molar mass of 180 g/mol.

• C3H6O3

• C5H10O5

• C6H12O6

• C4H8O4

What is percentage yield in a chemical reaction?

• Percentage yield is the ratio of the actual yield to the theoretical yield, multiplied by 100 to give a percentage.

• Percentage yield is the ratio of the theoretical yield to the actual yield.

• Percentage yield is the sum of the actual yield and theoretical yield.

• Percentage yield is the amount of reactants left after a reaction.

In a reaction, if 10g of A reacts with 20g of B to produce 15g of C, what is the percentage yield?

• 90%

• 80%

• 50%

• 75%

How is the limiting reactant determined experimentally?

• By flipping a coin

• By asking a magic eight ball

• By conducting a reaction using known amounts of each reactant and observing which one is completely consumed first.

• By consulting a horoscope

Calculate the percent composition of nitrogen in ammonia (NH3).

• 90.12%

• 68.29%

• 82.31%

• 75.46%

If a compound has an empirical formula of CH and a molar mass of 78 g/mol, what is its molecular formula?

• C2H2

• CH4

• C6H6

• C3H3