module 2- foundations in chemistry Flashcards
1
Q
heavy water
A
contains two atoms of the 2^H [D] isotope
2
Q
heavy water bp
A
101.40
3
Q
heavy water mp
A
3.80
4
Q
heavy water density
A
1.11
5
Q
water bp
A
100.00
6
Q
water mp
A
0.00
7
Q
water density
A
1.00
8
Q
group 1 (ion charge )
A
1+
9
Q
group 2 (ion charge )
A
2+
10
Q
group 5 (ion charge )
A
3-
11
Q
group 6 (ion charge )
A
2-
12
Q
group 7 (ion charge )
A
1-
13
Q
ion group exceptions
A
Ag+, Zn2+
14
Q
cation
A
positive ion
15
Q
anion
A
negative ion
16
Q
oil rig
A
oxidation is loss, reduction is gain [of electrons]
17
Q
mass defect
A
the strong forces holding neutrons and electrons comes at the expense of the loss of mass {mass is lost to hold nucleus}
18
Q
standard isotope
A
base all atomic masses on - carbon 12
19
Q
mass spectrometer finds
A
the percentage abundances of in a sample of an element
20
Q
mass spec method
A
sample is vaporised/ ionised to get positive ions, the ions are accelerated. heavier ions move slower and are harder to deflect so they are separated, depicted as mass to charge ratio. each ion reading adds to signal, greater abundance = greater signal
21
Q
mass spec equation
A
mass/charge of ion
22
Q
for an ion with one positive charge- m/z ratio
A
ratio is equivalent to the relative isotopic mass
23
Q
metals on the left side of the periodic table (electrons )
A
lose electrons, to form cations
24
Q
non- metals on the right side of the periodic table (electrons)
A
gain electrons, to form anions
25
binary compound
2 elements
26
poly atomic
ion may contain atoms of more than one element
27
ammonium (molecular formula )
NH4
28
ammonium (ion charge)
1+
29
hydroxide (mf)
OH
30
hydroxide (ion charge )
1-
31
nitrate (mf)
NO3
32
nitrate (ion)
1-
33
nitrite (mf)
NO2
34
nitrite (ion charge )
1-
35
hydrogen carbonate (ion)
1-
36
hydrogen carbonate (mf)
HCO3
37
mangante [VII] (mf)
Mno4
38
mangante [VII] (ion)
1-
39
carbonate (mf)
CO3
40
carbonate (ion)
2-
41
sulfate (mf)
SO4
42
sulfate (ion)
2-
43
sulfite (mf)
SO3
44
sulfite (ion)
2-
45
dichromate (mf)
Cr207
46
dichromate (ion)
2-
47
phosphate (mf)
PO4
48
phosphate (ion)
3-
49
molecular formula - (brackets)
poly atomic
50
molecular formula is (charge )
neutral, the charges cancels out
51
diatomic molecule
2 atoms bonded together
52
state symbols
(g) = gas
(s) = solid
(l) = liquid
(aq) = aqueous - dissolved in water
53
examples of diatomic molecules
H2,N2,O2,F2,Cl2,Br2,l2
54
do covalent bonds have ions
do not
55
amount (n)
particles measured in the units moles
56
one mole [avogradros constant ]
6.02 x 10^23
57
one mole is equal to
the number of atoms in carbon 12
58
mass of one mole is equal to
atomic mass
59
molecular mass (m)
mass in grams of each mol in a substance /g mol -1
60
amount equation
amount = mass/molar mass
61
molecular formula
number of atoms of each elements in a formula
62
empirical formula
simplest ratio
63
Mr
add the ram/ compared to carbon 12 molecular mass
64
workout relative formula mass
add ram in emp formula
65
hydrated salts
water molecules are apart of the crystalline structure- water of crystallisation, shown as dot between compound and water
66
hydrated copper (II) sulfate [blue] is heated
is heated, the bond holding the water is broken, the water is evaporated, making white anhydrous copper sulfate- without water the crystalline structure is lost
67
method- hydrated salt
Weigh an empty crucible
Add hydrated salt and weigh
Heat over bunsen burner until it turns white, using a tripod and a pipe - clay triangle - about 4 mins
Cool then weigh the anhydrous salt
Experimental formula - assumptions - all water is lost, no further decomposition
68
cm =
ml
69
dm=
1000cm= 1 litre
70
concentration of solution
is the amount of solute in moles, dissolved in 1dm^3
71
standard solution
solution of known concentration
72
n=cxv
amount = conc x volume
73
molar gas volume
is the volume per mole of gas molecules, at stated temperature and pressure
74
room temperature and pressure (rtp)
20 degrees Celsius and 101 kpa
75
at rtp, 1 mol of gas molecules have a volume of
24.0 dm^3 = 24000cm^3
76
amount of mol =equation
volume/molar gas volume
77
ideal gas assumptions for the molecules
random motion/elastic collisions/negligible size/no inter molecular forces
78
pv = nrt
pressure x volume = amount x r x temperature
79
ideal gas constant (r) for water
8.314 j mol-1 k-1
80
cm^3 to m^3
x 10^-6
81
dm^3 to cm^3
x 10^-3
82
c to k
+ 273
83
Kpa to pa
x10^3
84
percentage yield
actual/theoretical x100
85
limiting reagent
not in excess, used first and stops the reaction
86
atom economy
based on balanced equation and assumes 100% yield
87
high atom economy
Produce a large amount proportion of desired product and few unwanted waste products
Are important for sustainability as they make the best use of natural resources, better for environment
88
atom economy equation
sum desired/ total sum x 100
89
finding relative molecular mass-practical
Add sample of volatile liquid to a small syringe via a needle, weigh the small syringe
Inject the sample into a gas syringe through the self sealing rubber cap, reweigh the small syringe to find the mass of the volatile liuid ]
Place in a boiling water bath at 100 degrees, the liquid vaporises producing a gas , the pressure is recorded
90
stoichiometry
balancing numbers give ratio of atoms in moles, of each substance
91
identifying an unknown metal
92
acid releases
H+
93
alkali releases
OH-
94
what is an acid
releases H+ ions when dissolved
95
+ aq
excess of water
96
hydrochloric acid
HCL
97
sulfuric acid
H2SO4
98
nitric acid
HNO3
99
ethanoic acid (vinegar)
CH3COOH
100
metal carbonates examples
Na2CO3, CaCO3, CuCO3
101
metal oxides
MgO, CaO, CuO
102
alkalis
NaOH, KOH, NH3
103
strong acids [dissociation ]
completely dissociates, releases all h atoms into soloution as h+ ioms
104
weak acids [dissociation ]
partially dissociates, only releases a small proportion of h+ ions
105
bases
metal oxides, metal hydroxides, metal carbonates and ammonia are all bases
106
base + acid -->
neutralises and forms a salt
107
what is an alkali
releases OH- ions into solution
108
carbonates + acid
salt + water + co2
109
dissociation in sulphuric acid
Sulfuric acid H2SO4 is a strong acid but this is true for only one of the 2 hydrogen atoms, when sulfuric is mixed with water each H2SO4 molecule dissociates releasing just one of its two
110
dissociation in sulphuric acid equations
hydrogen atoms, as an H+ ion :
H2SO4 (aq) → H+ (aq)+ HSO4- (aq)
The resulting hso4- (aq) ions then only partially dissociate
HSO4- (aq) ⇌ H+ (aq) + SO4 2- (aq)
111
hydrochloric acid formula
HCl
112
sulphuric acid formula
H2SO4
113
nitric acid formual
HNO3
114
ethanoic acid (vinega)
CH3COOH
115
HCl forms
chlorides
116
H2SO4 forms
sulfates
117
HNO3
nitrates
118
CH3COOH
ethanoate
119
sodium chloride (f)
NaCl
120
sodium sulfate
Na2SO4
121
calcium nitrate
Ca(NO3)2
122
ammonium ethanoate
CH3CO2NH4
123
titrations
technique to accurately measure the volume of one solution that reacts exactly with another solution
124
titration uses
1) find the concentrations of a solution
2) identification of unknown substances
3) purity of a substance
125
impurities can cause ....
harm eg. in medication
126
preparing a standard soloutionn- equipment
a volumetric flask is used to make up a standard solution accurately
127
standard solution
a solution of a known concentration
128
preparing a standard solution - method
1)The solid is first weighed accurately
2)The solid is dissolved in a beaker using less distilled water than will be needed to fill the volumetric flask.
3)The last traces of solution are rinsed into the solution with more distilled water
4) the flask is then carefully filled to the graduation line by adding distilled water a drop at a time until the bottom of the meniscus is lines up exactly with the mark. Care at this stage is essential - if too much water is added the solution will be to dilute and must be prepared again
5) the volumetric flask is slowly inverted several times to mix the solution thoroughly, makes consistent results
129
acid base titrations
The solution of an acid is titrated against a solution of a base using a pipette and burette
130
manufactured certainties - pipette and Burette
10cm3 pipette +- 0.04cm3
25cm3 pipette +_- 0.06cm3
50cm3 buirette +- 0.10 cm3
131
