C3 - stichometry

Question 1

naming compounds: metal, non-metal - rules

Answer 1

-metal first
non-metal has “ide” at end
eg. magnesium chloride

Question 2

naming compounds: non-metal, non-metal - rules

Answer 2

-hydrogen first
-non-metal with lower group goes first
-non-metal with lower down goes first
eg, hydrogen chloride, nitrogen dioxide, sulfur oxide

Question 3

define atomic mass

Answer 3

proton + neutron

Question 4

define atomic number

Answer 4

proton

Question 5

what is the standard measurement of atoms & why

Answer 5

-carbon 12
-most abundant element

Question 6

define relative atomic mass

Answer 6

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

Question 7

formula relative atomic mass of an element through its isotopes (Ar)

Answer 7

(mass number of isotope x % of type of isotope) + (….) / 100

Question 8

define relative molecular mass (Mr)

Answer 8

sum of relative atomic masses in molecular formula

Question 9

formula for relative molecular mass (Mr)

Answer 9

-mass of each element X no. of the element
-add them up
eg. H2O - >1 X 2 + 16 = 18

Question 10

define molecular formula

Answer 10

number and type of atoms in one molecule

Question 11

define empirical formula

Answer 11

simplest whole number ratio of atoms present

Question 12

define relative formula mass

Answer 12

sum of relative atomic mass in empirical formula

Question 13

law of mass conservation

Answer 13

mass cannot be created or destroyed

Question 14

formula for % purity of a substance

Answer 14

mass of pure substance in it
——————————————- X 100%
total mass

Question 15

formula for % yield of a substance

Answer 15

actual mass of product
——————————————- X 100%
theoretical mass of product
-actual mass = mass from mr & mol

Question 16

define mol

Answer 16

-unit of amount of substance
-1 mol = 6.02 x 10^23 particles

Question 17

formula for mol

Answer 17

mass
———————— = mol
molecular mass

Question 18

how much is Avogadro’s constant (NA) = 12g of Carbon 12 = mol worth

Answer 18

6.02 x 10^23 particles

Question 19

formula for number of molecules in a compound

Answer 19

6.02 x 10^23 X no. mols

Question 20

formula for number of atoms in a compound

Answer 20

6.02 x 10^23 X no. atoms in chemical formula

Question 21

formula for concentration

Answer 21

        volume -g/ dm^3

Question 22

1 mol at rtp volume?

Answer 22

24dm^3

Question 23

what does limiting reactant do

Answer 23

controls the amount of product made

Question 24

finding limiting reactant

Answer 24

-find mols
-compare mol with ratio
-smaller mol is the limiting reactant

Question 25

finding empirical formula from % mass

Answer 25

-% mass/ molecular mass = no. mol
-no. mol/ smallest no. mol = ratio of the elements
eg. K - 26.57/ 39 = 0.68, O - 38.07/ 16 = 2.38, Cr - 35.36/ 52 = 0.68
0.68/ 0.68 = 1, 2.38/ 0.68 = 3.5, 0.68/ 0.68 = 1
-1: 3.5:1 = 2: 7: 2

Question 26

addition reaction

Answer 26

only 1 product

Question 27

substitution reaction

Answer 27

-one substance swaps with another

Question 28

combustion reaction

Answer 28

reaction of a fuel with oxygen

Question 29

decomposition reaction

Answer 29

only 1 reactant

Question 30

define tire

Answer 30

amount needed for a complete reaction to occur