Compounds and Stoichiometry

Question 1

A _______ is a pure substance composed of two or more elements in a fixed proportion.

Answer 1

Compound

Question 2

A _______ is a combination of two or more atoms held together by covalent bonds.

Answer 2

Molecule

Question 3

This term represents the empirical formula of an ionic compound.

Answer 3

Formula unit

Question 4

______ _______ is the sum of the atomic weights of all the atoms in a molecule, and its units are _____.

Answer 4

Molecular weight; amu (atomic mass units)

Question 5

How would you determine the molecular weight of carbon dioxide? What units would you use?

Answer 5

You would add the atomic weights of the individual atoms together to determine the molecular weight, which is always reported in amu (atomic mass units).

Question 6

Define a mole. What is another name for the actual number of particles defined by a mole, and what is the number itself?

Answer 6

A mole is the number of atoms found in 12 grams of carbon-12. Another name for the mole is Avogadro’s number: 6.022 X 10^23.

Question 7

The mass of one mole of a compound is called its _____ mass and is usually reported in grams per mole.

Answer 7

Molar

Question 8

The amount of a compound, measured in grams, that produces one equivalent of the particle of interest is called the ______ ______ weight and can be calculated from what equation?

Answer 8

Gram equivalent; molar mass/n

Question 9

Normality is given in what units?

Answer 9

equivalents/liter

Question 10

What is the equation for molarity in terms of normality?

Answer 10

Normality/n, where n is the number of protons, hydroxide ions, electrons, or ions produced or consumed by the solute.

Question 11

The law of _____ _____ states that any pure sample of a given compound will contain the same elements in identical mass ratio.

Answer 11

Constant composition

Question 12

The ______ formula gives the simplest whole-number ratio of the elements in a compound.

Answer 12

Empirical

Question 13

The ______ formula gives the exact number of atoms of each element in the compound and is a multiple of the empirical formula.

Answer 13

Molecular

Question 14

The _____ ______ of an element (by mass) is the percent of a specific compound that is made up of a particular element.

Answer 14

Percent composition

Question 15

What is the formula for percent composition?

Answer 15

(Mass of element in formula/molar mass) x 100%

Question 16

A metathesis reaction is another name for what type of chemical reaction?

Answer 16

A double-displacement reaction

Question 17

A _____ reaction is a specific type of double-displacement reaction in which an acid reacts with a base to produce a salt (and, usually, water).

Answer 17

Neutralization

Question 18

One mole of any ideal gas at STP is equal to what volume?

Answer 18

22.4 L

Question 19

The reactant consumed first in a chemical reaction is known what?

Answer 19

The limiting reagent (or reactant)

Question 20

Reactants that remain after all the limiting reagent has been used up are known as _____ _____.

Answer 20

Excess reagents

Question 21

What equation is used to calculate percent yield?

Answer 21

(Actual yield / theoretical yield) x 100%

Question 22

When an element forms two oxyanions, the name of the one with less oxygen ends in -___, and the one with more oxygen ends in -___.

Answer 22

-ite; -ate

Question 23

Solutes that enable solutions to carry currents are called ______.

Answer 23

Electrolytes