1.4: Composition of Mixtures

Question 1

Substance

Answer 1

-has distinct properties
-has a composition that does not vary from sample to sample

Question 2

Element

Answer 2

substance that cannot be decomposed into simpler substances

Question 3

Compound

Answer 3

substance that can be decomposed into simpler substances because it is made up of more than one element

Question 4

The Law of Constant Composition / The Law of Definite Proportions

Answer 4

-compounds have a definite composition
-the relative number of atoms of each element in the compound is the same in any sample

Question 5

Mixture

Answer 5

-doesn’t come in a fixed ration
-comprised of >1 pure substances
-varied composition

Question 6

Heterogeneous Mixture

Answer 6

mixture that varies in composition throughout a sample

Question 7

Homogeneous Mixture / Solution

Answer 7

mixtures that have the same composition throughout a sample

Question 8

Elemental Analysis Purpose

Answer 8

-determine the quantity of a particular element within a molecule or material
-two types:
-qualitative
-quantitative

Question 9

Qualitative Analysis

Answer 9

determining what elements are present or the presence of a particular element

Question 10

Quantitative Analysis

Answer 10

determining how much of a particular or each element is present

Question 11

Mass Percentage Formula

Answer 11

(mass of substance / total mass of mixture) x 100

Question 12

Combustion Analysis

Answer 12

-compounds containing C, H, and O are routinely analyzed through combustion in a chamber
-mass of C is determined from the mass of CO2 produced
-mass of H is determined from the mass of H2O produced
-mass of O is determined by the difference of the mass of the compound used and the total mass of C and H