Stoichiometry

Question 1

Stoichiometry

Answer 1

The area of study that examines the quantities of substances consumed and produced in a chemical reaction.

Question 2

Chemical Equations

Answer 2

Represent chemical reactions

Question 3

+ sign in a chemical reaction means:

Answer 3

Reacts with

Question 4

the —–> sign in a chemical reaction means:

Answer 4

Produces

Question 5

Coefficients in a chemical equation

Answer 5

Indicate the relative number of molecules of each kind involved in the reaction

Question 6

Reactants

Answer 6

the starting substance in a reaction

-on the left side of the arrow

Question 7

Products

Answer 7

substances produced in the reaction

-on the right side of the arrow

Question 8

Balanced equation

Answer 8

when there are equal numbers of atoms on each side of the chemical equation.

Question 9

Symbols for state and what they mean:

Answer 9

(aq) aqueous
(g) gas
(l) liquid
(s) solid

Question 10

Combination Reactions

Answer 10

when two or more substances react to form one product

Question 11

Decomposition Reactions

Answer 11

When one substance undergoes a reaction to produce two or more other substances.

Question 12

Combustion Reaction

Answer 12

rapid reactions that produce a flame and most have atmospheric O2(g) as a reactant reacting with a hydrocarbon and they produce CO2 (g), and often H2O.

Question 13

quantitative Significance

Answer 13

the subscript and coefficients in the equation represent precise quantities.

Question 14

Formula Weight

Answer 14

The sum of the atomic weights of the atoms in the chemical formula of the substance.

Question 15

Molecular Weight

Answer 15

The mass of the collection of atoms represented by the chemical formula for molecule.

Question 16

Formula Unit

Answer 16

is the mass of a collection of ionic substances.

–NaCl for example

Question 17

Percentage Composition

Answer 17

the percentage by mass contributed by each element in the substance

Question 18

Percentage Composition of an element formula

Answer 18

(((Number of atoms of element)x(Atomic Weight of element))÷(Formula Weight of Substance))x 100

Question 19

Mole (mol)

Answer 19

the counting unit for numbers of atoms, ions, or molecules in a laboratory-size samples

Question 20

Avogadros’s Number

Answer 20

6.022 x 10^23

Question 21

Molar Mass

Answer 21

the mass in grams of one mole of a substance (g/mol)

Question 22

Procedure to find the empirical formula

Answer 22

Mass % of element
-(assume 100g sample)
Grams of each element
-use molar mass
Moles of each element
-calculate mole ratio
Empirical Formula

Question 23

How to find the Molecular formula from the Empirical Formula

Answer 23

Whole-number multiple = Molecular Weight ÷ Empirical Formula Weight

Question 24

Limiting Reactant

Answer 24

the reactant that is completely consumed in a reaction

Question 25

Excess reactant

Answer 25

the other reactants that are not the limiting reactant

Question 26

Theoretical yeild

Answer 26

the quantity of product calculated to form when all of a limiting reactant is consumed

Question 27

Percent Yield

Answer 27

relates actual and theoretical yeilds

Question 28

Percent yield formula

Answer 28

Percent yield =

(actual yield ÷ Theoretical yield) x 100