Experimental techniques and Stoichiometry Flashcards
1
Q
How will oxygen be represented as if there are 3 elements in a compound and one of them is oxygen
A
compound name will end in ate or ide
2
Q
Order of two elements in compound
A
element further to left on periodic table comes first in name
3
Q
How will the compound end if there are only 2 elements
A
second element will end in -ide
4
Q
Exception to rules (Hydroxide) (2)
A
hydroxide usually exists as a compound with 3 elements
however it ends with -ide
5
Q
Exception to rules (Ammonium) (2)
A
Ammonium exists as a compound with 3 elements
however it ends with -ide
6
Q
Cations and Anions order in compound name (2)
A
cations come first
anions come second
7
Q
How does a prefix help in a chemical formula
A
prefix helps to show the number of atoms for an element
8
Q
Prefix for one
A
mono
9
Q
prefix for 2
A
di
10
Q
prefix for 3
A
tri
11
Q
prefix for 4
A
tetra
12
Q
prefix for 5
A
penta
13
Q
prefix for 6
A
hexa
14
Q
When is valency method used
A
when compound has no prefix
15
Q
What does a roman numeral signify of an element
A
the valency of the element
16
Q
When is radical method used
A
when compound has more than 2 elements
17
Q
What is a radical (2)
A
group of elements bonded together
exist as ions
18
Q
Name the radicals (7)
A
Hydroxide
Hydrogen Carbonate
Nitrate
Ammonium
Carbonate
Sulfate
Phosphate
19
Q
What is the overall charge of an ion
A
0
20
Q
Hydroxide radical
A
OH -
21
Q
Hydrogen carbonate radical
A
HCO - 3
22
Q
Nitrate radical
A
NO - 3
23
Q
Ammonium radical
A
NH + 4
24
Q
Carbonate radical
A
CO 2- 3
25
Sulfate radical
SO 2- 4
26
Phosphate radical
PO 3- 4
27
Purpose of word equations
represent what happened during chemical reaction
28
Definition of reactants
chemicals at the start of the reaction
29
Definition of products
new substances formed during reaction
30
Order of word equations (3)
reactants start
products end
seperated by arrow
31
Define a chemical equation
names of chemicals within word equations replaced with chemical formulae
32
Name the Diatomic elements (7)
Hydrogen
Nitrogen
Fluorine
Oxygen
Iodine
Chlorine
Bromine
33
State symbol for solid
s
34
State symbol for liquid
l
35
State symbol for gas
g
36
State symbol for solution (aqueous)
aq
37
Why are chemical equations balanced
law of conservation of mass - mass cannot be created or destroyed
38
Define Ionic equations
Equations which show reactions involving ions
39
Define spectator ions (2)
ions present in reaction but don't take part
appear unchanged on both sides of chemical equation
40
Unit given to mass of atom (3)
called atomic mass unit
symbol : u
can also be called Dalton (Da)
41
Define relative atomic mass (3)
measured in relation to carbon-12 atom : because carbon-12 mass is exactly 12
mass number on periodic table
average mass of naturally occurring isotopes of element
42
Define relative molecular mass
overall mass of compound
43
Purpose of percentage of mass calculations
determine percentage of certain element in compound
44
Percentage by mass formula
m/Mr x 100
45
Define the independent variable (4)
variable deliberately changed during investigation
is cause
is on x-axis
is on left column for table
46
Define the dependent variable (4)
variable measured during investigation
is effect
is on y-axis
is on right column of table
47
Define a control variable
factors controlled during investigation
48
Define a fair investigation
investigation in which only one variable is changed (independent variable)
49
Measuring cylinder function
measure volume of liquid to be used in reaction
50
Pipette function
transfers volume of liquid from one vessel to another
51
Burettes function (4)
used in titration reactions
allow volumes of liquid to be added to another
addition of liquid controlled by tap
scientist able to measure how much liquid needed in reaction
52
Define precise results
set of results close to each other
53
Define accurate results
results close to actual value
54
How does filtration work (2)
insoluble solid get stuck in filter paper
liquid easily passes through
55
Filtration function
separates insoluble solid from solution
56
Define residue
insoluble solid left after filtration
57
Define filtrate
liquid seperated
58
Function of evaporation (2)
separates soluble solid from liquid
liquid evaporated to leave soluble solid behind
59
Define a pure substance
substance having only one type of particle
60
Define an impure substance
substance which has more than one type of particle
61
Melting/boiling point for a pure substance (2)
sharp melting/boiling point
set temperature at which IMFs break (as they are all the same)
62
What is the melting/boiling point for an impure substance (2)
differing melting/boiling point
separate components melt at different temperatures
63
Pure substance molecular structure
specific arrangement of atoms/molecules
64
Impure substance molecular structure (2)
contains more than one type of particle
original arrangement of pure substance altered
65
Impure solid melting and boiling point compared to pure solid
impure solids will have a lower melting point
66
What happens during melting of a pure substance (3)
particles arranged in regular pattern held together by intermolecular forces
intermolecular forces begin to break as substance begins to melt
molecules aren't held as tightly as before which disorders arrangement of atoms
67
What happens during melting of an impure substance (3)
substance begins to melt before melting point reached
other substances get in between original substance, breaking intermolecular forces
substance begins turning into a liquid as intermolecular forces begin to break
68
Why is purity important (2)
important for food and pharmaceutical industries
impurities can be harmful and need to be checked
69
Define crystals
small, regularly shaped solids which reflect light
70
Examples of crystals (2)
salt
copper sulfate
71
Are crystals usually soluble
yes
72
Function of crystallisation
allows pure crystals of solid to be obtained from solution
73
How does crystallisation work (3)
crystals form when temperature of solution decreases
as a result, solid particles have less space in the liquid
solid particles are pushed out of solution and grow as crystals
74
Function of distillation (3)
separate liquid from soluble solid
obtain liquid solvent
separates mixture of liquids with different boiling points (however temperature difference between mixtures must be 50 degrees C or above)
75
How distillation works (3)
solvent boils in solution, turning into a gas
travels into condenser where it meets cool atmosphere and condenses into liquid
solute remains in flask while solvent collected as distillate
76
Purpose of fractional distillation (2)
separate more complex liquid mixtures
used when difference in boiling point of separate components is roughly 25 degrees C
77
How fractional distillation works (5)
same set up with distillation
components of mixture have similar boiling points and vaporise at same time
components travel up flask and meet cool glass beads
glass beads condense liquid with higher boiling point and cause it to drop back in round bottom flask
liquid with lower boiling point travels along condenser
78
Where is fractional distillation used (2)
crude oil industry to separate crude oil
separated into petrol, diesel and kerosene
79
Chromatography purpose
used to separate small quantities of substance from a solution
80
Define stationary phase in chromatography (2)
part that doesn't move
e.g filter paper
81
Define the mobile phase in chromatography (2)
part that moves
e.g solvent which moves spots up paper
82
Setting up chromatography procedure (4)
solvent used must start below baseline - otherwise spots travel into solvent
baseline done in pencil
paper sits vertically and is upright by a wooden splint
spots travel up stationary phase at different rates causing them to separate
83
What is responsible for how far spots travel (2)
mass of spots - smaller mass greater distance
solubility of spots - more solubility greater distance
84
Purpose of Rf values (2)
substances have unique Rf values
known Rf values compared to unknown Rf value to find substance
85
Rf formula
distance moved by spot from baseline/distance moved by solvent front from baseline
86
Conditions for keeping Rf values the same (3)
same type of chromatography
same conditions
same solvent used
87
Purpose of paper chromatography (2)
used to test for impurities in substance
impure substance has more spots than expected
88
What does 0K equal to in degrees celsius
-273 degrees celsius
89
What does 1 L equal to in decimetres cubed
1
90
What does 1 L equal to in cm cubed
1000
91
SI measurement for mass
kilogram
92
SI measurement for length
metre
93
SI measurement for time
second
94
SI measurement for amount of substance
mole (mol)
95
SI measurement for electric current
ampere (A)
96
SI measurement for temperature
kelvin (K)
