Ch. 3 Rx and Stoichiometry

Question 1

What is Avogadro’s number?

Answer 1

6.022 x 10^23 (this is a mole)

Question 2

What is percent composition?

Answer 2

The percent of the total mass of a compound that a particular element contributes

Question 3

How do you calculate percent mass?

Answer 3

Total molar mass (element)/molar mass (compound) x100 = percent

Question 4

How do you find the mass of a compound?

Answer 4

add each individual atom mass

Question 5

How do molecular formula and empirical formula differ?

Answer 5

The molecular formula is though of as the normal way to write a formula (C6H12O6)
The empirical formula is the most reduced form of that molecule (CH2O)

Question 6

When given empirical formula and a molar mass, how would you determine the molecular formula?

Answer 6

1. ) determine the actual mass of the molecule
2. ) then divide the empirical by molecular, which gives the multiplier.
   3) multiply coefficients by the multiplier

Question 7

How would you determine the empirical formula, when given grams?

Answer 7

1. ) determine the mole ratio, divide gram mass by elemental mass.
2. ) Divide moles by the lowest mole
3. ) plugin value for coefficients

Question 8

How would you find an empirical formula from percent?

Answer 8

1. ) assume 100%, and change the percent to grams
2. ) convert grams to moles
3. ) divide by the smallest number of moles

Question 9

How do electrons move in a Reduction reaction?

Answer 9

gain of electrons

Question 10

How do electrons move in an oxidation reaction?

Answer 10

Loss of electrons

Question 11

Redox reactions most often occur in which compounds?

Answer 11

Ionic

Question 12

When sodium forms with chlorine, which is reduced?

Answer 12

Chlorine, it readily accepts 1 electron

Question 13

You identify a limiting reagent by calculating the

Answer 13

amount of product that would form from complete Rx of each element

Question 14

Limiting reagent is always the smallest unit (T/F)

Answer 14

False

Question 15

How do you calculate theoretical yield?

Answer 15

Theoretical yield is how much the limiting reagent produces

Question 16

How do you calculate the percent yield?

Answer 16

divide the amount of limiting reagent given by the theoretical yield, (actual/theoretical) and multiply by 100

Question 17

What is the atomic weight of hydrogen?

Answer 17

1 amu

Question 18

What is the atomic weight of carbon?

Answer 18

12 amu

Question 19

What are the 7 different reaction types?

Answer 19

synthesis
decomposition
single displacement
double displacement
neutralization
combustion
REDOX

Question 20

Decomposition reactions are the reverse action of synthesis as such, they can be labeled as ______ reactions. This means?

Answer 20

Endothermic

They require energy to break bonds

Question 21

In a displacement reaction, which species is replaced?

Answer 21

The atom that is more reactive.

Metals and halogens are typically replaced

Question 22

In what type of reaction will an acid and a base react to form salt and water?

Answer 22

Neutralization

Question 23

Neutralizations always result in a neutral pH (T/F)

Answer 23

False. The salt produced could be acidic or basic