Chemistry Test Chapter 09

01. Which of the following is the correct value for Avogadro's number?

• 6.022 × 10²³
• 6.23 × 10²²
• 6.023 x 10²²
• 6.22 x 10²³

02. The official definition of Avogadro's number is based on the number of atoms in exactly 12 g of ________.

• nitrogen-14
• hydrogen-1
• oxygen-16
• carbon-12

03. One mole of water contains of hydrogen atoms and of oxygen atoms.

• two moles; one mole
• one mole; two moles
• one mole; one mole
• two moles; two moles

04. An element's atomic mass, expressed in atomic mass units on the periodic table, is equal to its ________ mass.

• actual
• molar
• theoretical
• empirical

05. Molar mass is typically expressed in which unit?

• g/mol
• u/mol
• kg/mol
• none of these

06. Which of these types of formulas typically takes the most time and space to draw?

• structural
• molecular
• stoichiometric
• empirical

07. A(n) ________ formula tells you what elements are present and gives the simplest whole-number ratio of atoms in the compound.

• structural
• molecular
• mathematical
• empirical

08. What type of formula best represents the arrangement of bonds in a molecule?

• molecular
• empirical
• structural
• ionic

09. Which principle states that the ratio of elements in a compound is constant for every particle in that compound?

• law of conservation of matter
• law of multiple proportions
• second law of thermodynamics
• law of definite composition

10. You can calculate the percent composition of a compound directly from its formula if you know

• the molar mass of the compound.
• the molar mass of each element in the compound.
• the density of each element in the compound.
• the units of measurement of the compound.