Unit 2 Flashcards
1
Q
Name two tests for water :
A
Anhydrous copper(II) sulfate Anhydrous cobalt (II) chloride
2
Q
Colour changes of anhydrous copper (II) sulfate ?
A
White solid to blue
3
Q
Anhydrous cobalt (II) chloride colour changes:
A
Pale blue to pink
4
Q
What is hard water ?
A
Water that doesn’t readily form a lather with soap
5
Q
What is soft water
A
Water that readily forms a lather with soap
6
Q
What is hardness in water caused by ?
A
Ca2+ or Mg2+ ions
7
Q
What is the chemical name for soap ?
A
Sodium Stearate
8
Q
What does boiling do?
A
Removes temporary hardness
9
Q
What is temporary hardness caused by ?
A
Dissolved calcium hydrogen carbonate
10
Q
Formula for temporary hardness arising in water
A
CaCO3 + H2O + CO2 -> Ca(HCO3)2
11
Q
How does temporary hardness arise in water?
A
Limestone reacts with rainwater containing dissolved carbon dioxide to form calcium hydrogen carbonate solution
12
Q
Equation for boiling
A
Ca(HCO3)2 (aq) -> CaCO3(s) + CO2(g) + H2O(l)
13
Q
What does an ion exchanger do ?
A
Removes both perm. And temp.
Dissolved Ca2+ ions in hard water are removed and replaced by Na2+ ions from the ion exchange resin
14
Q
What is the chemical name for washing soda
A
Hydrated sodium carbonate
15
Q
What does washing soda do?
A
Removes both temp. And perm.
Dissolved calcium or magnesium ions are removed due to a reaction with carbonate ions from the washing soda t form insoluble calcium carbonate or magnesium carbonate
16
Q
Advantages and disadvantages ir hard water
A
Hard water tastes better
It’s good for health teeth and bones
But
It produces a scum with soap (wastes soap)
17
Q
What does desiccant mean
A
Drying agent
18
Q
Anhydrous calcium chloride
A
White solid absorbs water from the air until eventually a colourless solution forms
19
Q
Self-indicating Silica gel colour changes
A
Blue to pink
20
Q
Normal silica gel colour changes
A
White and remains white when it absorbs moisture from the air
21
Q
What does hygroscopic mean
A
Absorbs moisture from the air
22
Q
Why is fluoride added to drinking water ?
A
It prevents tooth decay
23
Q
Why do some people not like fluoride being added to drinking water ?
A
It can cause stomach cancer
24
Q
What is barium sulfate used for?
A
Patients with stomach intestinal problems to X-ray the stomach or bowel
25
Why is barium sulfate safe to use ?
It has a low solubility in water so it cannot act as a poison in the body
26
What does exothermic mean ?
Gives out heat
27
What does endothermic mean ?
Takes in heat
28
What do all chemicals possess ?
Internal energy- energy is required to break all types of bonds
29
What is bond breaking ?
Endothermic
30
What is bond makeing ?
Exothermic
31
What is thermal decomposition ?
A substance breaks down when heated
32
What is the general equation for thermal decomposition ?
Metal carbonate -> metal oxide + carbon dioxide
33
What are the most common examples used in thermal decomposition ?
Copper (II) carbonate
| Calcium carbonate
34
What colour is copper carbonate ?
Green solid
35
Colour changes of copper carbonate when heated ?
Green to black solid= copper oxide, co2 released
36
What colour is calcium carbonate ?
White solid
37
What is calcium carbonate used for ?
To remove acidic impurities from the iron ore in the blast furnace
38
What happens when CaCO3 is heated ?
It glows orange and co2 gas is release
39
What happens in a line kiln?
Limestone (CaCO3) is decomposed into lime (calcium oxide)
40
Process in lime kiln ?
Hot air is blown into lime kiln to burn coke and heat calcium carbonate until it decomposes,
41
What is calcium carbonate used for ?
Agriculture- neutralise the acidity in soil water. Also used as an antacid in stomach to reduce excess stomach acidity
42
Mining limestone advantages and disadvantages??
It provides employment, provided better transport links
But
It creates an eyesore and causes dust pollution
43
What is the atmosphere?
The collection of gases that surrounds the earth
44
What is air ?
The atmosphere near the surface
45
Percentages of air in atmosphere?
79% nitrogen , 20% oxygen, 1% argon, 0.03% water vapour and carbon dioxide
46
What is today's atmosphere ?
An oxidising one
47
What causes changes in the atmosphere?
Photosynthesis
Carbonate rocks being formed
Fossil fuels being formed over time
48
What theory did Alfred wegener propose ?
Continental drift in 1912
49
What is continental drift?
The con indie BT's on the surface of the earth are moving and that th y were one single land mass millions of years ago- since then th have drifted away from each other
50
Examples to back up continental drift theory.?
Shape of continents - South America would fit exactly into Africa
Fossil fuels found in continents that he proposed were once joined were very similar
Similar species of animals
51
Why do tectonic plates move ?
Due to the convection currents in the liquid mantle
52
Describe what happens when plates collide directly with each other ?
Mountain ranges can be formed
53
What happens when plates are pulled apart from each other ?
Formation of volcanoes - liquid part of the mantle l reaches the earths surface- - lava
54
What happens when plates try to move past each other ?
Earthquakes
55
What is a redox reaction?
One where oxidation and reduction both occur simultaneously
56
What is oxidation?
Gain of oxygen
Loss of electrons
Loss of hydrogen
OILRIG- Electrons
57
What is reduction ?
The gain of hydrogen
Loss of oxygen
Gain of electrons
OILRIG- electrons
58
What is the chemical name for rust ?
Hydrated iron(III) oxide
59
What two conditions are required for rusting ?
Moisture( water) air (oxygen)
60
Example of an investigation to fine out the factors of rusting ?
Three test tubes - one with ion nail and water only
Second with ion nail, boiled water and layer of olive oil
Third with suspended iron nail and anhydrous calcium chloride
61
How to prevent rusting ?
1. Painting
2. Alloying
3. sacrificial protection
62
What can be painted onto the metal to prevent rusting ?
1. Paint - cars bridges etc
2. Oil or grease- tools and machinery
3. Plastic coating - cover bicycle handlebars
4. Plating with another metal e.g tin -making cans for food or chromium- vehicle bumpers ( bother are applied to steel by electrolysis
63
What is sacrificial protection?
Bars of magnesium can be added to ships etc to prevent rusting. The magnesium corrodes instead of he iron or steel but must be replaced with fresh magnesium periodically
64
What is galvanising ?
Iron can be coated in zinc , zinc oxidises to form a layer of zinc oxide
65
What is alloying ?
Allot is a mixture of two or more elements , at least one of which is a metal
66
Combustion of carbon?
C + O2 -> CO2
67
Incomplete combustion of carbon ?
2C + O2 -> 2CO
68
What happens when magnesium is burned with oxygen ?
Grey metal to a bright white light releasing heat and forming a white powder
69
Observations of sulfur with oxygen ?
Yellow powder melts to a red liquid and burns with a blue flame releasing heat and forming a colourless pungent gas called sulfur dioxide
70
What gas is used to reduce metal oxides e.g copper(II) oxide ?
Hydrogen
71
Observations of copper 2 oxide being reduced ?
Black copper oxide changes to a pink colour and condensation is present in the tube
72
Why is excess hydrogen burnt when reducing copper oxide ?
To prevent flammable hydrogen gas bulking up in the laboratory
73
What four things does the rate of a reaction depend on. ?
Surface area of solid particles
Concentration
Temperature
Catalyst
74
What reactions are used in rate of reaction experiments?
1. Metal reacting with a dilute acid- produces hydrogen gas
2. Marble chips reacting with HCL produces water and carbon dioxide
3. Catalytic decomposition of hydrogen peroxide- produces oxygen
75
What is effervescence ?
Bubbling
76
What does cotton wool do when measuring a change in mass ?
Stops any liquid loss from the flask
77
Method of measuring a change in mass ?
1. 1g of large marble chips in a conical flask and HCL with cotton wool at the top on top of an electronic balance
2. Then repeat with 1g of smaller marble chips
3. Plot a graph showing the results
78
Measuring gas volume ?
Collect the gas in a gas syringe
79
What apparatus is needed for measuring gas volume ?
```
Thistle funnel
Delivery tube
Conical flask
Bung
Gas syringe
HCL
Marble chips
```
80
Formula for rAte?
Rate= 1/time
81
What are the units of rate v?
S-1
82
What is activation energy ?
The minimum energ that the colliding particles need to react l
83
Why does a higher temperature speed up the rate of a reaction ?
The particles have more energy and move faster
This leads to more collisions
More successful collisions in a given period of time- activation energy can be overcome
Increases rate of reaction
84
How does having a higher concentration of a solution increase the rate of a reaction ?
There are more particles present in the same volume
This leads to more collisions between the particles
More successful collisions in a given period of time
Increases the rate of the reaction
85
Tips for graphs that have a higher temp?
Gas volume starts at zero
Gas volume gets higher every time
The line levels off earlier
Line ends at same final gas volume
86
What is a catalyst?
A substance that speeds up the rate of a reaction without being used up itself
87
How do catalysts work?
They lower the activation energy when ch increases the number of successful collisions in a given period of time
88
What catalyst is used in the decomposition of hydrogen peroxide ?
Manganese (IV) oxide
89
What catalyst is used in the contact process ? (Sulfuric acid )
Vanadium (V) oxide
90
What catalyst is used in the haben process ? ( ammonia )
Iron
91
What do manufacturers want to achieve the maximum of ?
Yield
92
Why might manufacturers prefer getting a lower yield ?
Factors can be expensive
93
Why might high pressure for gases not be used ?
It is expensive and can be dangerous for staff
94
What is a compromise temperature ?
Allows enough of the product to be made in as short time period as possible
95
Why might using s better catalyst be more effective and sustainable ?
1. Using less energy - reduces the temperature and pressure required
2. Using renewable raw material
3. Being carried out in fewer steps - saves waste
96
How do you collect indelible gases ?
Collection over water - trough , beehive shelf , gas jar, delivery tube
97
How do you collect soluble gases ?
Downward or upward delivery
98
When do you use downward delivery ?
Soluble gas , denser than air
99
When do you use upward delivery ?
Soluble gas, less dense than air
100
What is hydrogen?
Colourless odourless gas, - collection over water
101
Observations of hydrogen gas with air?
Clean blue flame , producing water vapour
102
What is the equation for the haben process ?
N2 + 3H2 2NH3
103
What do you use to prepar hydrogen ?
Zinc of magnesium and HCL
104
What is a test for hydrogen ?
Lit splint , squeaky pop
105
What is hydrogen used for ?
Rocket engines
Clean fuel
Weather balloons
106
Why is hydrogen described as a clean fuel ?
Because the only product of combustion is non-polluting
107
What is charcoal ?
An impure form of carbon which is a black solid
108
Observations of combustion of carbon ?
Orange flame forming a colourless odourless gas called carbon dioxide
109
How is carbon dioxide prepared ?
From calcium carbonate and HCL
110
How is carbon dioxide collected ?
Over water
111
Physical properties of carbon dioxide ?
Colourless odourless gas
112
What does carbonic acid do ? And how is it formed ?
Causes the acidity in dizzy drinks
| Carbon dioxide reacts with water to form the weak acid- carbonic acid
113
Observations of carbon dioxide and magnesium?
Bright white light, white solid produced and there are black specks (carbon)
114
What is a test for carbon dioxide ?
Bubble gas through limewater
| The colourless solution becomes milky
115
What is carbon dioxide used for ?
In fire extinguishers
| Dry ice
116
What is nitrogen ?
Colourless and odourless gas
117
How do you collect nitrogen ?
Collection over water
118
Why is nitrogen unreactive ?
Because of the triple covalent bond between the nitrogen atoms in N2 molecules. The triple covalent bond requires substantial energy to break before the nitrogen atoms can react
119
How do you prepare nitrogen ?
Removing carbon dioxide oxygen and water vapour from s sample
120
What is the haber process ?
450 degrees Celsius
Pressure of 200atm
Iron catalyst
The double arrow represents a reversible reaction
121
What is nitrogen used for ?
Foot packaging
| Liquid- coolant
122
What is ammonia ?
A colour less pungent gas
123
How is ammonia collected ?
Upward delivery
124
Test for ammonia ?
Dip a glass rod in HCL and put this in a sample of gas
| White smoke of ammonium chloride produced of ammonia is present
125
Nitrogenous fertilisers ?
Excessive us of nitrogenous fertilisers on soil leads to leaching if nitratesbinto soil water and finally into river waters. This leads to eutrophication
126
What can increased levels of nitrates do ?
Lead to stomach cancer and also blue baby syndrome
127
What is eutrophication?
Nitrogenous fertilisers in rivers and lakes leads to excess algae growth
This leads to death of algae
Decomposing microorganism use up oxygen gas in the water breaking down dead algae
This leads to a lack of oxygen and the death of fish
128
Observations of Aqueous ammonia and copper ions?
Pale blue precipitate of copper hydroxide
| Excess- redissolves to form a dark blue solution
129
Aqueous ammonia with iron (II) ions ?
Pale green precipitate of iron hydroxide
| Excess-doesn't tedussolve
130
Aqueous ammonia and iron(III) ions ?
Red brown precipitate
| Excess- doesn't redissolve
131
Aluminium and aqueous ammonia ?
White precipitate
| Excess- doesn't resissolve
132
Aqueous ammonia and zinc ions ?
White precipitate
| Excess - redissolve stop form colourless solution
133
Aqueous ammonia and magnesium ?
White precipitate
| Excess- doesn't redissolve
134
What is oxygen ?
Colourless odourless gas
135
How is oxygen collected ?
Collection over water ?
136
How is oxygen prepared ?
Hydrogen peroxide and manganese (IV) oxide
137
Test for oxygen ?
Apply a glowing splint and the glowing splint will relight
138
What is oxygen used for ?
Welding
Medicine
Rocket engines
139
Oxygen and hydrogen v?
Clean blue flame pro slicing a colourless odourless gas that condenses to form a colourless liquid ( water)
140
Oxygen and carbon ??
Black solid burns with and orange sooty flame forming a colourless gas (co2 )
141
Oxygen and sulfur ?
Yellow solid sulfur melts to a red liquid and burns with a clue flame giving a colourless pungent gas (SO2 )
142
Oxygen with zinc ?
Grey cooks glows red on heating producing a yellow solid which changes to a white solid on cooling zinc oxide
143
Oxygen with iron?
Grey solid burns with oranges sparks producing a black solid
144
Copper reactions ?
Red pink solid glows and forks a black solid
145
What is sulfur ?
Brittle yellow solid
146
Allotropes of sulfur ??
Rhombic sulfur
Monoclinic sulfur
Plastic sulfur
147
What are allotropes ?
Alternative forms of the same element in the same physical state
148
Sulfur and iron?
Yelllow sulfur and grey iron glows red when heated forming s black sold
149
What is sulfur dioxide ?
Colourless pungent gas
150
How is sulfur dioxide collected ?
Downward delivery
151
What does acid rain do ?
Corrodes limestone buildings
Defoiliates trees
Pollutes lakes
152
How to prevent acid rain?
Remove sulfur from fossil files before burning
| Use renewable energy resources
153
What is the contact process stages ?
1. Combustion of sulfur s+O2-> SO2
2. Catalytic production of sulfur trioxide
450 here's pressure of 2 atmospheres
Catalyst of vanadium five oxide
2SO2+ O2 ~ 2SO3
3. Absorption in concentrated sulfur of acid
Forms oleum
SO3+ H2SO4 -> H2S2O7
4. Dilution of oleum
H2S2O7 + H2O-> 2H2SO4
154
What is sulfuric acid used fo ?
Car batteries
155
What is the chemical name for sugar ?
Sucrose
156
Reaction of sulfuric acid and sugar ?
Sugar swells up and rises in container
Heat is released and there is a distinct caramel smell together with a pungent odour
A black solid is formed
157
Why is water not directly added to sulfuric acid ?
It produces a corrosive mist
158
Formula for percentage of element X in a compound?
Number of atoms of X in compound x RAM of x/ RFM of compound x 100
159
Formula for dilution factor ?
Dilution factor = total volume of diluted solution / volume of original solution to be diluted
160
How do you work out the number of miles of a solid in a solution ?
Moles = solution volume x concentration / 1000
161
Colour changes of phenolphthalein ?
Acid to alkali - pink to colourless
| Alkali to acid - colourless to pink
162
Colour changes of methyl orange?
Acid to alkali - yellow to red/orange
| Alkali to acid- red to yellow/ orange
163
How do you prepare a pipette ?
Rinse it with deionised water
Rinse with solution to be used
Use a pipette filler to draw up the solution Neil the bottom of the meniscus is on the line
164
How do you prepare a Burette?
Rinse with deionised water
Rinse with solution to be used
Fill burette with solution ensuring the key is filled and there are no air bubbles
Read volume at the bottom of the meniscus
165
Method of titration?
Measure volume is put into pipette
Few drops of indicator are added to the conical flask and the solution is mixed
Burette is filled with the second solution
Second solution is run out of the Burette and into the conical flask while the conical flask is being swirled until the indicator changed colour
Volume of solution added from Burette is recorded - titre
Titration carried out three times
166
What can raw materials can you get from earth?
Like , salt
167
From the sea ?
Water , sodium chloride
168
From the air ?
Oxygen and nitrogen
169
From crude oil?
Plastics patrol
170
From living things
Cotton wool wood
171
What are natural materials ?
Those derived directly from raw materials
172
What are synthetic materials ?
Those which are man made
173
What is silver nitrate is used for ?
Wound dressings in hospitals - kill bacteria which prevents the wound from becoming infected
174
How are metals high in the reactivity series extracted ?
Electrolysis
175
How are metals low in reactivity dries extracted ?
Reduction with carbon
176
What is an electrolyte ?
The liquid or solution that conducts electricity and is then decomposed by it
177
What is the negative electrode called ?
Cathode - positive ions attract to it
178
What is the positive electrode called ?
Anode- negative ions attracted to it
179
Why do all electrolytes conduct electricity ?
Free ions that can move and carry charge
180
What is aluminium ore ?
Bauxite
181
What does bauxite form when purified ?
Alumina
182
Why is alumina dissolved in molten cryolite?
To reduce its melting point
183
What does a crust of aluminium oxide do?
It keeps heat in
184
What are the anode and cathode made out of in extraction of aluminium from its ore ?
Carbon
185
Why does the carbon anode have to be replaced periodically?
Due to its reaction with oxygen it wears away
186
What is the solid material that is put into the last furnace called?
The charge
187
What is the charge made up of ?
Iron ore , limestone and coke
188
What is iron ore called ?
Haematite
189
What is the reducing agent ?
Carbon monoxide
190
What is the steps on the extraction of iron in the last furnace.
1. Production of reducing agent
2. Reduction of iron ore to iron
3. Removal of acidic impurities
191
Advantages and disadvantages of recycling ?
Saves resources
Fewer eyesores created
But labour intensive
192
Advantages and disadvantages of disposal by incineration or landfill ?
Heat energy from incineration can be harnessed to generate electricity
But Landfill wastes land
193
Advantages and disadvantages of production of ne material s?
Workforce must be skilled
| But more raw materials used
194
What is polymerisation?
The process of creating a long molecule from small molecules which form the repeating unit in the polymer
195
What is addition polymerisation ?
The process of adding molecules together to form a polymer as the only product
196
What is a monomer ?
He simple molecule from which a polymer is formed
197
What is fermentation?
Sugar solution is mixed with yeast in warm conditions in the absence of oxygen to produce carbon dioxide and ethanol
