Unit Test Answers

A year has 365 days, and a day has 24 hours. If an hour has 60 minutes and a minute has 60 seconds, how many seconds are there in 1 year?

The following balanced equation shows the formation of ammonia.N2 + 3H2 2NH3How many moles of nitrogen are needed to completely convert 6.34 mol of hydrogen?

What is the molar mass of fluorine, F2?

The equation below shows lithium reacting with nitrogen to produce lithium nitride.6Li + N2 2Li3NIf 12 mol of lithium were reacted with excess nitrogen gas, how many moles of lithium nitride would be produced?

A teacher wants to figure out the amount of a solution that is needed for a titration experiment in a class lab. The class has 15 students, and each experiment needs 50 mL of solution. If each student will perform the experiment two times, how many mL of solution will the teacher need for the whole class?

Avogadro’s number was calculated by determining the number of atoms in

How would you write 16,340 in scientific notation with 2 significant figures?

Zachary adds 26.64 g to 12.557 g. How many significant figures should his answer have?

The balanced equation below shows the products that are formed when pentane (C5H12) is combusted. C5H12 + 8O2 5CO2 + 6H2OWhat is the mole ratio of oxygen to pentane?

Which expression is equal to the number of grams (g) in 2.43 kilograms (kg)?

The hydrogen ion concentration of a vinegar solution is 0.00010 M. How is this concentration written in scientific notation?

Consider the balanced equation below. 2H2S + 3O2 2SO2 + 2H2OWhich option gives the correct mole ratios?

The volume of a sample of water is 2.5 milliliters (mL). The volume of this sample in liters (L) is

Which must be the same when comparing 1 mol of oxygen gas, O2, with 1 mol of carbon monoxide gas, CO?

Which statement best describes a mole?

The mass of a single atom of carbon can be found by dividing the atomic mass (12.01 g) by 6.022 1023. Which is the mass of a single carbon atom, correctly written in scientific notation with the correct number of significant figures?

Which is the molar mass of H2O?

Consider the balanced equation below.4NH3 + 3O2 2N2 + 6H2O What is the mole ratio of NH3 to N2?

The O–O bond length in oxygen gas is 1.20741 10–10 m. The atomic radius is exactly of the O–O bond length. Which is the atomic radius of oxygen, correctly written in scientific notation with the correct number of significant figures?

Consider the equation below.N2 + 3H2 2NH3What is the mole ratio of hydrogen to ammonia?

Henry divides 1.060 g by 1.0 mL to find the density of his water sample. How many significant figures should he include in the density value that he reports?

Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?

William adds two values, following the rules for using significant figures in computations. He should write the sum of these two numbers by using

Andi performs the calculation that is shown below.How should the answer be reported using the correct number of significant figures?

What is the molar mass of CHCl3?