Chemistry Quiz

A student has a 1 g sample of each of the following compounds: NaCl, KBr, and KCl. Which of the following lists the samples in order of increasing number of moles in the sample?

• NaCl < KCl < KBr

• NaCl < KBr < KCl

• KCl < NaCl < KBr

• KBr < KCl < NaCl

A student obtains a sample of a pure solid compound. In addition to Avogadro’s number, which of the following must the student know in order to determine how many molecules are in the sample?

• Mass of the sample, volume of the sample

• Mass of the sample, density of the sample

• Molar mass of the compound, mass of the sample

• Molar mass of the compound, density of the sample

Which of the following numerical expressions gives the number of particles in 2.0 g of Ne?

• 6.0 x 10^23 particles/mol / 2.0 g

• 6.0 x 10^23 particles/mol / 20.18 g/mol

• 2.0 g / 20.18 g/mol (6.0 x 10^23 particles/mol)

• 20.18 g/mol / 2.0 g (6.0 x 10^23 particles/mol)

According to the information in the table above, a 1.00 g sample of which of the following contains the greatest mass of oxygen?

• Na₂O

• MgO

• K₂O

• CaO

Given that the density of Hg(l) at 0°C is about 14 g mL⁻¹, which of the following is closest to the volume of one mole of Hg(l) at this temperature?

• 0.070 mL

• 0.14 mL

• 1.4 mL

• 14 mL

• 28 mL

A solution of methanol, CH₃OH, in water is prepared by mixing together 128 g of methanol and 108 g of water. The mole fraction of methanol in the solution is closest to

• 0.80

• 0.60

• 0.50

• 0.40

• 0.20

A solution is prepared by adding 16 g of CH3OH (molar mass 32 g) to 90. g of H2O (molar mass 18 g). The mole fraction of CH3OH in this solution is closest to which of the following?

• 0.1

• 0.2

• 0.3

• 0.4

• 0.6

In 1.00 mol of potassium zirconium sulfate trihydrate, K4Zr(SO4)4 · 3 H2O, there are

• 3 x 6.02 x 10^23 hydrogen atoms

• 6.02 x 10^23 sulfur atoms

• 4 x 6.02 x 10^23 potassium atoms

• 4 moles of oxygen atoms

• 4 moles of zirconium atoms

How many carbon atoms are contained in 2.8 g of C2H4?

• 1.2 x 10^23

• 3.0 x 10^23

• 6.0 x 10^23

• 1.2 x 10^24

• 6.0 x 10^24