Gcse What You Got Wrong Flashcards
Why are compounds always pure
Because they are always within a fixed ratio of atoms
What is an element
A substance that consists of only one type of atom
That can not be broken down any simpler by chemical means
Describe the arrangement of gases
A= random and widely spread out
M= move randomly in all directions and freely
P= rarely in contract with each other
As the temperature increases, what happens to the solubility of a gas
It decreases
In, the experiment for measuring solubility, state the word equation for the calculation at the end
Mass of crystals dissolved= (mass of crystals + basin) - (mass of basin)
Mass of water that evaporated (that the solvent was orignal dissolved in )= (mass of basin + solution )- (mass of basin + crystals)
Explain how the diffusion of potassium permanganate (iv) happens in water
Particles move from a high concentration to a low concentration
This is because there are gaps in the liquid and particles in a liquid are able to Slide Over each other
Therefore they can easily mix together
Explain why as temperature increases, solubility of a solid also increase
Because the solvent molecules have more kinetic energy
This means that they can more efficiently break apart solute molecules held together by intermolecular forces of attraction
Describe the structure of ionic substances, giant covalent substances, and metallic substances
Ionic:
-giant ionic lattice
-ions are regularly arranged
-and positive and negative ions repeat in a pattern
Giant covalent:
-giant lattice structure
-number of atoms is invariable
- so repeats on in 3D
Metallic
-giant metallic lattice
- held together by electrostatic attraction between positive ions and sea of delocalized
In the electrolysis of aluminum oxide, what deposits at the bottom
Molten aluminum
Why is diamond hard
Because of the rigid tetrahedral structure
How can you measure the initial volume of air, when measuring percentage of oxygen in the air using iron
Fill the connecting tube and the flask with water and then measure this out in a measuring cylinder
Explain how the phosphorus experiment works when measuring the percentage of oxygen in the air
-phosphorus is placed on an evaporating dish, on top of a trough of water in a bell jar
- it reacts with the oxygen in the air to form phosphorous oxide, a white smoke, which dissolves in the water
-this makes the water levels rise, and so you can measure the water levels before, and then the water levels after
What is the word equation for the thermal decomposition of metal carbonates
Metal carbonate—-) metal oxide + carbon dioxide
Give 5 word equationexamples of how carbon dioxide can be produced
Copper carbonate —-) copper oxide + carbon dioxide (thermal decomposition)
Calcium carbonate —-) calcium oxide + carbon dioxide (thermal decomposition)
Calcium carbonate + hydrochloric acid ——) calcium chloride + carbon dioxide + water
Carbon + oxygen —-) carbon dioxide
Petrol + oxygen —-) carbon dioxide + water
Give the balanced symbol equation for the reaction between calcium carbonate and hydrochloric acid
CaCO3(s) + HCL(aq) -—-) CaCl2 (aq) + CO2(g) + H2O(l)
Give the balanced symbol equation, using petrol to make carbon dioxide
2CH8H18 + 2O2 ——) 16CO2 + 18H2O
(This is the complete combustion of fuels, which always make carbon dioxide and water)
Describe an experiment to measur oxygen in the air, using iron WOOL
Soak iron wool on acetic acid to catalyse the reaction
Push into a measuring cylinder and then invert inside trough of water
Measure initial volume of air
As iron reacts with oxygen, the water level will rise to replace the space taken up by oxygen
Measure the final volume of oxygen
Give the equation to test that carbon dioxide has been given off
Bubbled in lime water to produce a white précipite of calcium carbonate
Ca(OH)2 + CO2 ——-) CaCO3 + H2O
When you keep bubbling carbon dioxide in a solution of calcium carbonate and water, give the balanced symbol equation of what happens and the colour change
CaCO3 + H2O + CO2 ——) Ca(HCO3)2(aq)
Colourless
State three substances that can be used to show combustion reactions, and give the flame colours produced aswell
Magnesium —-) white flame
Sulfur —-) dark blue flame
Hydrogen—-) pale blue flame
State the balanced symbol equation when magnesium oxide reacts with water, and when sulfur dioxide reacts with water
MgO+ H2O —-) Mg(OH)
SO2 + H2O —-) H2SO3 (SULFUROUS ACID)
Metal oxides are… in water
Non metal oxides are…. In water
Insoluble
Soluble
Describe the reaction between calcium and water
Slow reaction
Bubble form
White insoluble calcium hydroxide forms
In a colorless solution
Describe the reaction with magnesium with water and or steam
Does not react with water, because insoluble magnesium hydroxide layer is formed
Reacts with steam, to form magnesium oxide, which burns with a bright white flame. Also produces hydrogen
General word equation for metal and steam
Metal + steam —) metal oxide + hydrogen
Describe what happens to zinc in steam, and then iron in steam, with the colours
Zinc oxide formed, which is yellow upon heating but white upon cooling
Iron tetroxide formed, which is a darker grey
Describe the reaction between aluminum and hot and cold acid
Cold acid:
Reacts slowly and then vigorously,
Forms a layer of aluminum oxide, so the reaction stops
Hot acid: aluminum oxide layer is formed so reacts more vigorously
Describe the reactions of magnesium, zinc, and iron in hydrochloric acid
Magnesium:
- vigorous reaction
- rapid fizzing
-becomes hot
-colourless solution
Zinc:
-steady reaction
-steady fizzing
-becomes warm
- colourless solution
Iron:
-slow reaction
- fizzing
-slightly warm
- pale green solution
When iron reacts with hydrochloric acid, what colour is formed
Green pale solution
What two types of displacement reactions can you use to determine the reactivity of metals,
And then for each type state what will happen to the more reactive metal and then the less reactive metal.
-Metals with metal oxides, upon heating
-Metals with aqueous solutions of metal salt.
With metal oxides, more reactive metal is oxidized (as it binds more strongly to oxygen,
and less reactive metal is reduced
With aqueous solutions of metal salts, more reactive metal dissolves as it forms a solution
Less reactive metal coats the surface of the more reactive metal
Oxidizing agent defintion
Substance that oxidizes something else
So is reduced
What does the reactivity of metals depend upon
Their ability to from positive ions and lose electrons
Give the symbol way of writing hydrated iron (iii) oxide
Fe2O3.xH2O
Balanced symbol equation for the process of rust
4Fe + 3O2 + H2O —-) 2Fe2O3.XH2O
Galvanizing utilisés which two methods
Sacrificial protection
And the barrier method
percentage of argon in the air
0.9%
give the colours of the flames produced with the combustion reactions of sulphur, magnesium, hydrogen
sulfur, blue
magnesium, bright white
hydrogen, pale blue
give the thermal decomposition word equation reaction for a metal carbonate
metal oxide + carbon dioxide
give the word equation for the reaction between metal carbonate and acid
salt + carbon dioxide + water
give three ways that carbon dioxide can be produced
thermal decomposition of metal carbonates.
metal carbonate and acid, (react to form co2, salt, water)
combustion of fossil fuels
thermal decomposition of calcium carbonate has occurred. it is bubbled through lime water. what colour will it turn and what is produced
white precipitate,
because the decomposition results in the formation of carbon dioxide, when this bubbles in calcium hydroxide, it forms calcium carbonate and water
state the word equation for carbon dioxide is continuously bubbled through calcium hydroxide for a long time
calcium carbonate + carbon dioxide + water—— calcium hydrogen carbonate
reaction between,
metal + water
metal oxide + water
metal + steam
metal hydroxide + hydrogen
metal hydroxide
metal oxide + hydrogen
give descriptions of the reaction between,
magnesium +hcl
zinc + hcl
iron +hcl
vigorous,hot test tube, colourless
rapid reaction, warm test tube, colourless
slow reaction,slightyl warm, pale blue
what are two types of displacement reactions that can occur
combustion of metal oxide
reaction of metals with aqueous metal salt solutions
what is an ore
a rock that contains enough of the metal to extract it
what is a mineral
element or compound that occurs naturally
what is the relationship between steel and iron
steels are alloys of iron, mixed with different amounts of carbon
properties and uses of copper
unreactive
conducts electricity
malleable
pots and pans
electrical wires
water pipes
properties and uses of aluminium
resists corrosion
conducts electricity
low density
pots and pans
electric wires
car bodies
properties and uses of mild carbon steel
corrodes easily,
malleable
nails
carbodies
properties and uses of high carbon steel
brittle and hard,
cutting tools,
bridges
properties and uses of stainless steel
resists corrosion
strong
cutlery
sinks
stainless steel is an alloy of what
carbon and nickel
what is an alloy. then explain why alloys are harder than pure metals
alloys are mixtures of a metal with one or more other elements.
hard because has different sized atoms
which disrupts the regular lattice structure
so harder for the layers of ions to slide over each other
what colour does phenolphthalein and methyl orange turn in acid, and alkali solutions
phenolpthalein;
acid-colourless
alkali-pink
methyl;
acid-red
alkali; yellow
give 5 things to do in a titration to ensure accuracy
and give the value for results to be concordant
-use a white tile underneath
-swirl the solution to mix
-use water to rinse the flask at the end
-use a pipette with a pipette filler for an accurate reading
-always measure burette reading from bottom of the meniscus
concordant results are 0.2 + or_
an acid base reaction occurs and effervescence occurs. explain what type the base used was
base was a metal carbonate
bc when metal carbonate reacts with acids, co2 is given off which produces effervescence
Give four example of bases
Metal Carbonates
Metal oxides
Metal Hydroxides
Ammonia in solution
An acid is a proton..A bass is a proton…
Donor
Acceptor
Why must a titration be used to make a soluble salt of potassium sodium or ammonium
Because they are soluble in water, so it would not be known when the reaction is finished, and so exactly how much acid to add
What is the flame test colour for calcium
Orange
Describe how to carry out a precipation reaction for cations, and then give the observations made for each cation
Dissolve the salt in distilled water to form a solution (needs to be a solution for it to occur)
Add dilute sodium hydroxide
Observe the precipitate
Copper 2+—) blue
Ammonium ions, in cold—-) a smell. Ammonia in hot—-) red litmus turns blue
Iron 2+——) green
Iron 3+—-) brown
Describe what will happen to the colour of the precipitate if left out for a while, in the precipitation reaction of iron 2+
The iron (ii)hydroxide formed from the reaction will react with oxygen in the air to form iron (iii) hydroxide
Give the test for chlorine gas
1)take DAMP blue litmus paper and place in solution
2)will first turn red as chlorine dissolves in water to form an acidic soltuion
3)but will then turn it white because it beaches the paper
Give the test for carbonates
-add hydrochloric acid to the salt solution
-if fizzing is given off, this means a gas is produced
-and so test that the gas is carbon dioxide by bubbling it through limewater, to turn milky
Give the test for sulfates
-add hydrochloric acid to a solution of barium chloride (added to get rid of any carbonate or sulfite ions which could also form a précipitate)
-add this solution to the salt solution which is dissolved in distilled water
-a white precipitate of barium sulfate will form