Unit 3

Question 1

Particle

Answer 1

Smallest unit that is represented by a chemical formula

Question 2

What is an atom?

Answer 2

A single symbol
Ex. Ne

Question 3

What is a molecule ?

Answer 3

More then one covalent atom bonded together

Question 4

What is a formula unit?

Answer 4

An ionic compound made of multiple particles including ionic and covalent atoms.

Question 5

What is an ion?

Answer 5

An atom, molecule, or formula unit with a charge.

Question 6

What is formula mass?

Answer 6

Atoms+Simple ions (atomic mass)
For entities with more then one atom, sum of all masses in the formula

Question 7

How do you calculate formula mass?

Answer 7

Add mass of all atoms in formula using the mass given on the period table.

Question 8

What is % composition?

Answer 8

Relative mass of each element in a compound.

Question 9

How do you find the % composition.

Answer 9

Divide the mass of an element by the mass of the compound and multiply by 100.

Question 10

Law of definite proportions

Answer 10

The elements in a chemical compound are always present in the same proportions by mass.

Question 11

Stoichiometry

Answer 11

Numerical relationship between reactants and products in a chemical reaction

Question 12

Particle Ratio

Answer 12

Coefficients in a balanced chemical equation

Question 13

Equation to use particle ratio to find unkown quantities

Answer 13

unknown= known x unknown coefficient/known coefficient

Question 14

What is a Limiting Reactant?

Answer 14

Reactant that is completely consumed during a chemical reaction, limiting the amount of product produced

Question 15

What is a Excess Reactant(s)?

Answer 15

Reactants that are partially consumed by a reaction

Question 16

What is Avogadro’s Constant?

Answer 16

1 mole= 6.02 x 10(23) particles

Question 17

Mole Ratio is equal to what?

Answer 17

Particle ratio

Question 18

If the formula mass of carbon is 12 Da what is the molar mass?

Answer 18

12g/mol of carbon

Question 19

What is a mole?

Answer 19

The quantity of matter with a mass in g equal to its formula mass in Da

Question 20

What is molar mass?

Answer 20

The mass of one mole of any substance

Question 21

Equation for moles to mass

Answer 21

Mass= (quantity in mol) x (molar mass g/mol)

Question 22

Equation from mass to quantity in mols

Answer 22

Quantity in mol = mass/ molar mass g/mol

Question 23

When do you use mass stoichiometry?

Answer 23

When given a chemical equation and amount in grams.

Question 24

What is the line equation for mass stoichiometry?

Answer 24

Grams of known element x 1 x # of mols of unknown x formula mass of unknown/ formula mass of known/ # of mols of known/ 1

Question 25

What is yield?

Answer 25

Quantity of product produced from a given quantity of the limiting reactant

Question 26

What is theoretical yield?

Answer 26

-The amount of product predicted by stoichiometry
-maximum yield
-LR is completely consumed
-mass to mass calculation

Question 27

How do you find out theoretical yield?

Answer 27

Using the equation for mass stoichiometry

Question 28

What is actual yield?

Answer 28

Measured quantity obtained in a real chemical equation

Question 29

How to calculate % yield

Answer 29

actual yield/ theoretical yield x100%

Question 30

How to calculate actual yield

Answer 30

% yield/ 100% x theoretical yield

Question 31

What is the empirical formula?

Answer 31

Shows the lowest whole-number ratio of atoms of each element in a compound.

Question 32

What is the molecular formula?

Answer 32

Gives the actual number of atoms in each element in a compound.

Question 33

How to find empirical formula ?

Answer 33

Divide the mass in g of every element by the mass in Da
The lowest number is 1

Question 34

How to find molar mass?

Answer 34

Add atomic mass of every atom