Chapter 1

Question 1

Weighing Errors

Answer 1

1. samples must be at ambient temperature to prevent errors due to convective air currents.
2. Warmth of hands/fingertips can affect the apparent mass of an object.

Question 2

Buoyancy

Answer 2

The upward force exerted on an object in a liquid or gaseous fluid.

An object weighed in the air appears lighter than its actual mass by an amount equal to the mass of air that the object displaces.

Question 3

Ordinate

Answer 3

y-axis of a graph

Question 4

Abscissa

Answer 4

X-axis of a graph

Question 5

Solute

Answer 5

Minor species in a solution.

Question 6

Solvent

Answer 6

Major species in a solution

Question 7

Concentration

Answer 7

States how much solute is contained in a given volume or mass of solution or solvent.

Question 8

Mole (mol)

Answer 8

Avogadro’s number of particles (atoms, molecules, ions, etc).

Question 9

Molarity (M)

Answer 9

The number of moles of a substance per liters of solution.

Question 10

Atomic Mass

Answer 10

The number of grams containing Avogadro’s number of atoms.

Question 11

Molecular Mass

Answer 11

The sum of atomic masses of the atoms in the molecule.

Question 12

Electrolyte

Answer 12

A substance that dissociates into ions in solution.

Question 13

Formal Concentration (F)

Answer 13

The molarity of a strong electrolyte.

Question 14

Formula Mass

Answer 14

The molecular mass of a strong electrolyte.

Question 15

Molality (m)

Answer 15

Concentration expressed as moles of substance per kilogram of solvent (not total solution).

Question 16

Gravimetric Analysis

Answer 16

Chemical analysis based on weighing a final product.

Question 17

Stoichiometry

Answer 17

The calculation of quantities of substances involved in a chemical reaction.

Question 18

Volumetric Analysis

Answer 18

Procedures in which the volume of reagent needed to react with analyte are measured.

Question 19

Analyte

Answer 19

Substance being measured.

Question 20

Titration

Answer 20

A form of volumetric analysis in which increments of reagent solution - the titrant - are added to analyte until their reaction is complete.

Question 22

Equivalence Point

Answer 22

Occurs when the quantity of added titrant is the exact amount necessary for stoichiometric reaction with the analyte.

Question 23

End Point

Answer 23

Marked by a sudden change in physical property of the solution.

Question 24

Indicator

Answer 24

A compound with a physical property (usually color) that changes abruptly near the equivalence point.

Change is caused by disappearance of analyte or appearance of excess titrant.

Question 25

Blank Titration

Answer 25

A method of estimating titration error by which we carry out the same procedure *without* analyte.

Question 26

Direct Titration

Answer 26

Titrant is added to analyte until the reaction is complete.

Question 27

Back Titration

Answer 27

Add a known *excess* of one standard reagent to the analyte. Usefule when its end point is clearer than the end point of the direct titration.

Question 28

Gravimetric Titration

Answer 28

Titrant is measured by mass, not volume.