Chem Exam 1

Because they oxidized quickly where the oxide layer allows the liquid metal to wet the glas

• mixtures of elements

• compounds

• heterogenous mixture

• elements

Which one of the following is often easily separated into its components by simple techniques such as filtering or decanting?

• . mixture of elements

• compound

• homogeneous mixture

• heterogeneous mixture

• solution

The correct result (indicating the proper number of significant figures) of the following addition is

𝟏𝟐+ 𝟏. 𝟐 + 𝟎. 𝟏𝟐 +𝟎. 𝟎𝟏𝟐

• 13

• 13.3

• 13.33

• 13.332

• none of the above

Which of the following is an illustration of the law of constant composition?

• Water is a compound

• Water is 11% hydrogen and 89% oxygen by mass

• Water can be separated into other substances by a chemical process.

• Water and salt have different boiling points.

• Water boils at 100°C at 1 atm pressure

Which of the following is not an intensive property?

• Boiling point

• Melting point

• Mass

• Temperature

• Density

Which of the following is the highest temperature?

• 302 K

• 96 ℉

• 38 ℃

• None of the above

• The freezing point of water

Of the objects below, which is the densest?

• An object with a volume of 0.00212 m3 & a mass of 4.22 × 104 mg

• An object with a volume of 13 dm3 and a mass of 1.29 × 103 g.

• An object with a volume of 139 mL and a mass of 93 g.

• An object with a vol. of 3.91 × 10-24 nm3 & a mass of 7.93 × 10-1 ng

• An object with a volume of 2.5 L and a mass of 12.5 kg.

A lab technician uses a 10 mL pipette to measure the volume of a liquid in five trials. The expected volume is exactly 10 mL. The measurements obtained in the trials are: 10.7 mL, 9.5 mL, 9.8 mL, 10.1 mL, and 10.5 mL. How would you describe the accuracy and precision of this?

• The measurements are accurate but not precise

• The measurements are precise but not accurate

• The measurements are both accurate and precise.

• The measurements are neither accurate nor precise.

Which subatomic particles reside in the atomic nucleus?

• Protons, electrons

• Protons, neutrons

• Electrons, neutrons

• Neutrons only

• Protons only

Which pair of substances could be used to illustrate the law of multiple proportions?

• H2O, O2

• CH4, C6H12O6

• CO, CO2

• SO2, H2SO4

• NaCl, KCl