Quiz 1.2 Flashcards
What is a “chemical compound”?
a pure substance containing at least two different types of atoms that are
held to each other with chemical bonds.
How did Joseph Louis Proust study the composition of chemical compounds?
Proust used two different methods to analyze the composition of chemical compounds. The first
involved decomposing a known mass of compound into its elements and then finding the relative
proportions or percentages of those elements. The second method involved combining known
masses of two or more elements and then finding the mass of the compound produced.
What did Joseph Louis Proust find during his study of the composition of chemical compounds?
Proust’s studies showed that the percentage of each element present in a compound does not vary.
What is the formal name given to Joseph Louis Proust’s findings on the composition of chemical
compounds?
Law of Definite Proportions
What are the three general characteristics of chemical compounds found by Proust and others?
Chemical compounds are chemical combinations of two or more elements.
Chemical compounds have a definite (fixed) and constant (unchanging) elemental composition.Chemical compounds can be broken down into their constituent elements by chemical, but not
physical, means.
What is the meaning of the term “Formula Mass”?
the sum of the atomic masses of all the atoms present in one formula unit of a substance
What is an “atomic mass unit”?
1/12 the mass of a carbon-12 atom
What is the relationship between the terms “Formula Mass” and “Molecular Mass”?
used interchangeably
Why is it incorrect to use the term “Molecular Mass” when describing the mass of a substance like sodium chloride (NaCl) or magnesium sulfate (MgSO4)?
molecules are not their basic structural unit
Why is it preferable to use the terms “Formula Mass” and “Molecular Mass” instead of “Formula
Weight” and “Molecular Weight” when describing atomic, formula unit, or molecular quantities?
mass should technically be used over weight
