3.2 Stoichiometry

Question 1

What is relative atomic mass and symbol

Answer 1

The average mass of the isotopes of an element compared to 1/12 the mass of an atom of carbon - 12

Question 2

What is relative molecular Mass + symbol

Answer 2

The sum of the relative atomic masses in a molecule
Mr

Question 3

What is relative formula mass

Answer 3

The sum of relative atomic masses in ionic compounds

Question 4

What is avagadro’s number+symbol

Answer 4

6.02x10^23
NA

Question 5

“Law” about concentration

Answer 5

The greater the amount of solute in a given volume(solvent) the greater the concentration

Question 6

Concentration formula + units

Answer 6

c=n/v
g/dm3
(G/dm3=mol/dm3 x MR

Question 7

“Law” of volume of gas

Answer 7

One mole of any gas occupies a volume of 24 dm3

Question 8

What is a compound

Answer 8

A substance formed by the union of two or more elements.

Question 9

What is the law of conservation of mass

Answer 9

No atoms are lost or made in a chemical reaction, the atoms join together in different ways to form products

Question 10

Percentage yield formula

Answer 10

Actual yield/theoretical yield x 100

Question 11

Empirical formula of a compound

Answer 11

The simplest whole number ratio of the different atoms or ions in a compound

Question 12

molecular formula of a compound

Answer 12

Actual number for each type of atom in a compound
Number and type of different atoms in one molecule

Question 13

Percentage purity formula

Answer 13

(Atomic mass x number of mols of particular element in a compound)/molar mass of a compound x 100

Question 14

Concentration of a solution

Answer 14

Amount of solute dissolved in a solvent to make 1 dm3 of solution, the greater the amount of solute in a given volume, the greater the concentration.

Question 15

Concentration units

Answer 15

Mol/dm3

Question 16

How to convert from cm3 to dm3

Answer 16

Divide by 1000

Question 17

Room pressure

Answer 17

1 atm

Question 18

Volume of gas formula

Answer 18

V=n x 24

Question 19

Mass formula

Answer 19

m=n x M

Question 20

Molar mass unit

Answer 20

g/mol

Question 21

How to find molecular mass

Answer 21

Calculate the molar mass of the empirical formula
Relative molecular mass is divided by your answer
Multiply each elemnt in the empirical formula to get the answer

Question 22

How to find empirical formula

Answer 22

Change % into grams
Find number of mols
Divide each of the mols by the smallest number of mols
Times by the same whole numbers if you dont end up with whole numbers

Question 23

How can we ensure that we have the most amount of product in a reaction

Answer 23

When the product is produced in excess

Question 24

Limiting reagents

Answer 24

Limits amount of product formed

Question 25

The mole

Answer 25

Mass of a substance containing the same number of atoms/ions/molecules as there are in exactly 12.00g of 12carbon

Question 26

Covalent bond

Answer 26

Compounds formed when electrons are shared between atoms that are non-metal

Question 27

Define molecular formula of a compound

Answer 27

The number and type of different atoms in one molecule

Question 28

Define empirical formula of a compound

Answer 28

The simplest whole number ratio of the different atoms and ions in a compound

Question 29

What can concentration be measured in

Answer 29

g/dm3 or mol/dm3 (divide by mr)