2.1.3 amount of sustance

Question 1

what is the amount of substance
2.1.3(ai)

Answer 1

it means the number of particles

Question 2

what is the unit for amount of substance
2.1.3(aii)

Answer 2

mole

Question 3

what is Avogadro’s constant
2.1.3(aiii)

Answer 3

the number of particles per mole
6.02 x10(23) mol-1

Question 4

what is molar mass
2.1.3 (iv)

Answer 4

the mass of one mole of something
it has the same numerical value as mr
units are g mol-1

Question 5

what is molar gas volume
2.1.3(v)

Answer 5

if temperature and pressure stay the same one mole of any gas always has the same volume
it has the unit dm^3 mol-1

Question 6

empirical formula (the simplest whole
number rato of atoms of each element
present in a compound)
2.1.3(bi)

Question 7

molecular formula (the number and type of
atoms of each element in a molecule)
2.1.3(bii)

Question 8

calculatons of empirical and molecular formulae,
from compositon by mass or percentage
compositons by mass and relatve molecular
mass
2.1.3(c)

Question 9

what does hydrated mean
2.1.3(d)

Answer 9

contains water of crystalisation

Question 10

what does anhydrous mean
2.1.3(d)

Answer 10

contains no water of crystalisation

Question 11

what does water of crystallisation mean
2.1.3(d)

Answer 11

compounds crystallised from water frequently contain water molecules within their structure giving a crystal appearance to the compound. This water is known as the water of crystallisation

Question 12

calculaton of the formula of a hydrated salt from given percentage compositon, mass compositon or based on
experimental results
2.1.3(d)

Question 13

how to convert from moldm3 to gdm3
2.1.3(e)

Answer 13

x by the mr

Question 14

kpa to pa
2.1.3(f)

Answer 14

x 1000

Question 15

cm^3 to m^3
2.1.3(f)

Answer 15

/1 000 000

Question 16

degrees Celsius to kelvin
2.1.3(f)

Answer 16

+273

Question 17

use of stoichiometric relatonships in calculatons
2.1.3(g)

Question 18

the percentage yield of a reacton or related
quanttes
2.1.3(hi)

Question 19

the atom economy of a reaction
2.1.3(hii)

Question 20

PAG
2.1.3(i)

Question 21

why may you not get a 100% percentage yield
2.1.3(j)
LOOK AT SPEC AGAIN

Answer 21

-the reaction may be in equilibrium and not go to completion
-other side reactions may take place leading to side products
-the reactants may not be pure
-some of the reactants or products may be left in the apparatus used in the experiment