Stoichiometry

Question 1

Molecular formula

Answer 1

The number and type of different atoms in one molecule

Question 2

What does each formulas tell us?
Molecular
Structural
Empirical

Answer 2

The molecular formula chose you the actual number of atoms of each element in one molecule of the compound or element. The structural formula tells you the way in which the atoms in a particular molecule are bonded. The empirical formula is the simplest ratio of the atoms of each element present in one molecule or formula unit of the compound.

Question 3

Empirical formula

Answer 3

Formula that shows the simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound. ionic compound is always an empirical formula

Question 4

Relative atomic mass

Answer 4

The average mass of the isotopes of an element compound to 1/12th of the mass of an atom of C12

Question 5

Relative molecular mass (Mr)

Answer 5

The total mass of the molecule.

Question 6

Molar mass

Answer 6

The mass of one more of a substance for an element it’s the same as AR and for compound is the same as MR in grams

Question 7

The mole & Avogadro constant

Answer 7

The more is the SI unit of amount of substance one more of a substance contain in the same number of the stated particles atoms molecules or iron as one more of any other substance one more equals 6.02 x 10^23

Question 8

Volume of gas formula

Answer 8

Volume(dm^3) = mole x 24

Question 9

Mass formula

Answer 9

Mass = mole x Mr

Question 10

Finding the reacting masses

Answer 10

1. Information given in the question is used to find the amount in moles of the substance being considered.
2. The ratio between the substances is determine using balance in both equation
3. Once the moles has been determined they can be converted into grams or mass using the AR or Mr

Question 11

Limiting reactants

Answer 11

The chemical or reactant that is used at first in a chemical reaction which stops the duration of the reaction

Question 12

Steps of calculating limiting reactants

Answer 12

Write the balance equation for the reaction how can let them most of each reactants compare and deduce the limiting reactant

Question 13

Concentration formula

Answer 13

Moles = concentration x volume
Mol/dm^3

Question 14

Cm cube to dm cube

Answer 14

Cm to dm /1000
Dm to cm x1000

Question 15

G/dm^3 to mol/dm^3

Answer 15

/Mr
XMr

Question 16

Convert empirical formula to molecular formula

Answer 16

Mr of molecular formula/ Mr of empirical formula

Question 17

% yield

Answer 17

Used to describe the amount of product from a reaction

Question 18

Why is percentage yield never 100%

Answer 18

Reactants being left behind in the equipment

some products may be lost during separation purification stages

side reactions when a substance react with a gas in the air or an imparity in one of the reactants

loss of product during transfer from one container to another

Question 19

Percentage yield formula

Answer 19

Actual yield/theoretical yield x100

Question 20

Theoretical yield

Answer 20

The amount of product that would be obtained under perfect practical and chemical conditions

Question 21

Actual yield

Answer 21

The recorded amount of product obtained

Question 22

Percentage mass

Answer 22

Finding the percentage by mass of a element within a compound

Question 23

% mass

Answer 23

Total mass of the element in a compound/MR of the compound x100

Question 24

% purity

Answer 24

Used to calculate how pure the substance is with nothing else mix with it however the product can become contaminated with unnamed substances and impurities

Question 25

Percentage purity formula

Answer 25

Mass of pure substance/total mass of substance x100