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iGCSE Chemistry: Vth form BLACK HOLES

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What is meant by the term relative atomic mass, Aᵣ?
The average mass of an atom of an element, relative to 1/12th of the mass of an atom of carbon-12
Are metal oxides acidic or basic?
Basic
Are non-metal oxides acidic or basic?
Acidic
What is meant by the term empirical formula?
A chemical formula that shows the simplest ratio of the numbers of atoms in a compound
What is meant by the term molecular formula?
A chemical formula that shows the actual numbers of the different types of atoms in a molecule
State the formula for the copper (II) ion
Cu²⁺
State the formula for the iron (II) ion
Fe²⁺
State the formula for the iron (III) ion
Fe³⁺
State the formula for the lead (II) ion
Pb²⁺
State the formula of the hydrogen ion
H⁺
State the formula of the ammonium ion
NH₄⁺
State the formula of the carbonate ion
CO₃²⁻
State the formula of the hydroxide ion
OH⁻
State the formula of the nitrate ion
NO₃⁻
State the formula of the silver ion
Ag⁺
State the formula of the sulfate ion
SO₄²⁻
State the formula of the zinc ion
Zn²⁺
(Triple only) Are anions positively or negatively charged?
negatively
(Triple only) Are cations positively or negatively charged?
positively (ca+ions)
(Triple only) Explain, by referring to the electronic configurations, why lithium is less reactive than sodium.
Sodium has the electronic configuration 2,8,1 and lithium has 2,1. The outer electron lost from sodium is further from the nucleus therefore the electron is less attracted by the nucleus. So sodium is more reactive than lithium
(Triple only) Explain, by referring to the electronic configurations, why potassium is more reactive than sodium.
Sodium has the electronic configuration 2,8,1 and potassium has 2,8,8,1. The outer electron lost from potassium is further from the nucleus therefore the electron is less attracted by the nucleus. So potassium is more reactive than sodium
What are the elements in group 7 called?
Halogens
What colour and state is bromine at room temperature?
red-brown liquid
What colour and state is iodine at room temperature?
dark grey solid
What is the colour and physical state of chlorine at room temperature?
Green gas
(Triple only) Explain why bromine is less reactive than chlorine
Both chlorine and bromine react by their nucleus attracting an electron to fill their outer shell. The outer shell of bromine is further from the nucleus, so the attraction is weaker, making it less reactive.
(Triple only) Explain, by referring to the electronic configurations, why fluorine is more reactive than chlorine
Fluorine has the electronic configuration 2,7 and chlorine has 2,8,7. An extra outer electron is gained more easily by fluorine. This is because the outer shell is closer to the nucleus, so an extra electron is attracted more strongly.
What happens is a large amount of hydrogen is burnt?
Explosion
What observation is made when sulfur burns in air?
Blue Flame
When carbon burns in air, is the oxide acidic or basic?
Acidic
When magnesium burns in air, is the oxide acidic or basic?
Basic
Order these metals from the most reactive to the least: aluminium, calcium, copper, gold, iron, lithium, magnesium, potassium, silver, sodium, zinc
potassium, sodium, lithium, calcium, magnesium, aluminium, zinc, iron, copper, silver, gold
Which is more reactive: magnesium or aluminium?
magnesium
Which is more reactive: zinc or aluminium?
aluminium
Explain how galvanising prevent rusting
Zinc is more reactive than iron. Zinc reacts with oxygen instead of iron
What is sacrificial protection?
Sacrificial protection is when a more reactive metal is connected to a less reactive metal. Only the more reactive metal corrodes, so protecting the less reactive metal
(Triple only) State 2 properties that makes aluminium suitable for power cables
Ductile (drawn into a wire), conducts electricity and low density
(Triple only) State 3 properties that makes iron suitable for saucepans
Good conductor of heat, high melting point and malleable
(Triple only) What is an alloy?
An alloy is a mixture of a metal and one or more elements, usually other metals or carbon
State the colour of litmus in acidic and alkaline solutions
acidic = red alkali = blue
State the colour of methyl orange in acidic and alkaline solutions
acidic = red alkali = yellow
State the colour of phenolphthalein in acidic and alkaline solutions
acidic = colourless alkali = pink
Is sodium hydroxide soluble?
yes (All hydroxides are insoluble, except those of sodium, potassium and calcium (calcium hydroxide is slightly soluble))
Is calcium hydroxide soluble?
slightly (All hydroxides are insoluble, except those of sodium, potassium and calcium (calcium hydroxide is slightly soluble))
Is iron (II) hydroxide soluble?
no (All hydroxides are insoluble, except those of sodium, potassium and calcium (calcium hydroxide is slightly soluble))
Is iron (III) hydroxide soluble?
no (All hydroxides are insoluble, except those of sodium, potassium and calcium (calcium hydroxide is slightly soluble))
State the solubility rule for chloride salts
all are soluble, except silver chloride and lead chloride
State the solubility rule for hydroxide salts
all hydroxides are insoluble, except those of sodium, potassium and calcium (calcium hydroxide is slightly soluble)
What is defined as a proton acceptor?
An alkali
An acid is called a proton _________
An acid is a proton donor
In the flame test for copper (II) ions what colour is the result?
Blue-green
(Triple only) Explain, in terms of making and breaking bonds, why a reaction could be exothermic
The energy need to break the bonds is less than the energy released to make the bonds
(Triple only) In an endothermic reaction, which is greater: the energy taken in when breaking bonds or the energy released when bonds are made?
Breaking bonds
(Triple only) Is making new bonds exothermic or endothemic?
Exothermic
Explain the term functional group
A functional group is an atom or a group of atoms that determine the chemical properties of a compound
In car engines, sparks cause the formation of some gases which contribute to acid rain. What are these gases?
Oxides of nitrogen
Why can nitrogen react with oxygen in a car engine?
The temperature is very high
How does sulfur dioxide form in car engines?
Petrol includes the impurity sulfur, and when the petrol combusts some sulfur dioxide is formed
State the problem associated with sulfur dioxide in the atomosphere?
The sulfur dioxide combines with water in the atmosphere to form acidic solutions (acid rain)
(Triple only) Name 3 ways in which ethanol can be oxidised
1) Burning in air or oxygen (complete combustion). 2) Reaction with oxygen in the air to form ethanoic acid (microbial oxidation). 3) Heating with potassium dichromate(VI) in dilute sulfuric acid to form ethanoic acid
(Triple only) What is likely to be formed if ethanol is exposed to the air and undergoes microbial oxidation?
Ethanoic acid
(Triple only) What is the name for the oxidation of ethanol when it simply reacts with oxygen in the air?
Microbial oxidation
(Triple only) What is produced when ethanol is oxidised by heating with the oxidising agent potassium dichromate(VI) (K₂Cr₂O₇) in dilute sulfuric acid (H₂SO₄)?
Ethanoic acid
(Triple only) On way for ethanol to be oxidised, forming ethanoic acid, is to add potassium dichromate(VI) and what else?
Sulfuric acid
(Triple only) On way for ethanol to be oxidised, forming ethanoic acid, is to add sulfuric acid and what else?
potassium dichromate(VI)
Give two reasons why addition polymers are hard to dispose of
They are inert as they have strong C-C bonds. This makes them non-biodegradeable. Also, they produce toxic gases when burned.
What is the problem with burning addition polymers to dispose of them?
They produce toxic gases when burned.