Unit 3- Equations, The Mole, and Chem Formulas

Question 1

chem equations

Answer 1

a shorthand notation to describe a chem reaction

Question 2

reactants

Answer 2

substances consumed

Question 3

products

Answer 3

substances formed

Question 4

coefficient

Answer 4

s before the formula of a substance in equation

Question 5

Balancing equations

Answer 5

• start with most complex molecule and balance on either side. Move to next element. The last element will look at the product to balance the reactants
• if fraction, multiply WHOLE equation by the denom

Question 6

neutralization

Answer 6

the reaction of an acid with a base to form a SALT and WATER
(acid + base —> salt + water)

Question 7

acid

Answer 7

compound that dissolves water forming hydrogen ions

Question 8

base

Answer 8

dissolves in water forming hydroxide ions.
- usually soluble metal hydroxide

Question 9

salt

Answer 9

ionic compound consisting of the cation of a base and the anion of an acids

Question 10

balancing neutralization reactions

Answer 10

the # of hydrogen ions provided by he acid must equal # of hydroxide ions provided by the base (= to # of water molecules formed)

Question 11

combustion reaction

Answer 11

process of burning
- when hydrocarbon burns in oxygen, carbon forms CO2 and hydrogen forms H2O

Question 12

oxidation-reduction reactions

Answer 12

reaction in which electrons are transferred from 1 species to another

Question 13

assigning oxidation #s

Answer 13

1. an atom in its elemental state has an oxidation # of zero
2. The oxidation # of monoatomic ions is the charge of the ion
3. In combination with other elements, the oxidation # of F is -1, O generally -2, H generally +1 with nonmetal or -1 with metal. Other halogens are generally -1.
4. Sum of oxidation #s in any species must = charge of species

Question 14

oxidation

Answer 14

loss of electrons in reaction (ox # inc)

Question 15

reduction

Answer 15

gain of electrons in reaction (ox # dec)

Question 16

mole

Answer 16

amount of substance that contains as many entities as the # of atoms in exactly 12g of the 12C isotope of Carbon

Question 17

Avogadro’s #

Answer 17

the experimentally determined # of 12C atoms in 12g (= 6.022 x 10^23)

Question 18

converting moles to entities

and vice versa

Answer 18

moles x avogadro’s # = # atoms/molec

atoms/ avogardo’s # = moles

Question 19

molar mass (M)

Answer 19

the mass of one molec of that substance (g/mol) (= atomic mass)
- used to convert grams to moles and vice versa

Question 20

mass % from formula

Answer 20

atomic mass / mass of compound x 100%

Question 21

combustion

Answer 21

mass CO2(MM CO2) = molesCO2(CO2: C) = moles of C (MM C) = mass C
*same with H2O to H and O

Question 22

Calc Empirical Formula

Answer 22

mass or % mass(MM) = moles/ smallest mol = # become subscripts

*mass% –> assume 100g sample. % = g

Question 23

molec formula

Answer 23

whole # multiple of empirical formula

(empirical)n
n= MM of cpd/ MM of empirical formula

Question 24

stiochiometry

Answer 24

study of the quantitative relationships involving the substances in chem reactions

Question 25

formula for reaction stoichiometry

Answer 25

mass A(MM A) = moles A(coefficients A:B) = moles B(MM B) = mass B

Question 26

theoretical yield

Answer 26

max quantity of product that can be obtained from a chem reaction based on amounts of starting materials
(stoichiometry)

Question 27

limiting reactants

Answer 27

the reactant that is completely consumed when a chem reaction occurs
( stoichiometry but choose smaller mole to get mass of product)

Question 28

actual yield/ % yield

Answer 28

mass of the product in a reaction

% yield= actual yeild/ theoretical yield x 100%