Chemistry Semester 1 Exam Review

You find an unknown substance that cannot be separated by filtration, evaporation, or distillation. Would the explanation that this substance is an element be scientifically valid?

• Yes, because elements cannot be separated byordinary chemical means.

• Yes, because elements are pure substances made of one type of atom.

• No, because the substance could be a homogeneous mixture.

• No, because the substance could be a compound, which also cannot be separated by physical means.

We know that air is a mixture and not a compound because—

• it can be heated to a higher temperature

• it can be compressed to a smaller volume

• its components are chemically combined

• its composition can vary

A student collects the following data about a particular substance. Based on these data, calculate one intensive property, represented with the unit g/cm³, for this substance.

• 895g/cm³

• 8.95g/cm³

• .895g/cm³

• 8,950g/cm³

A typical aspirin dosage is described in milligrams. Using scientific notation, about how many milligrams of aspirin are in 0.000 325 kilograms?

• 3.25 x 10² mg

• 3.25 x 10⁴ mg

• 3.25 x 10^-4 mg

• 3.35 x 10^-4 mg

A student calculates that the volume of his textbook is 990.880 cm³. Which of the following is the volume written with 3 significant figures?

• 991 cm

• 990.9 cm

• 990.90 cm

• 991.000 cm

A metal sample has a mass of 45.65 g. The volume of the sample is 16.9 cm³. What is the density of the sample?

• 2.7 g/cm^3

• 2.70 g/cm³

• 0.370 g/cm³

• 0.37 g/cm³

A student accurately determines that the distance between two points on a football field is 105.0 feet. If there are about 3.28 feet in one meter, about how many meters is the distance? Express the answer using the correct number of significant figures.

• 32.0 m

• 344 m

• .0312 m

• 33 m

Which of the following states an important result of Rutherford’s gold-foil experiment?

• Atoms have mass.

• Electrons have a negative charge.

• Neutrons are uncharged particles.

• The atom is mostly empty space.

The alkaline earth metals are found in Group 2 of the periodic table. Which alkaline earth metal has the highest ionic radius based on its location on the periodic table?

• Beryllium (Be)

• Calcium (Ca)

• Magnesium (Mg)

• Radium (Ra)

Group 17 elements are the most reactive of the nonmetal elements because they—

• require only one electron to fill their outer energy level

• have the highest ionization energies

• have the largest atomic radii

• are the farthest to the right in the periodic table