FINAL BUFFER Flashcards
Alkali metals
Elements found in Group 1 of the periodic table
Why are they called alkali metals?
Because when reacted with water they form alkaline solutions
What are the typical poroperties of Group 1 elements?
Shiny when freshly cut, good conductors of electricity, solid at room temperature, soft
As you go down the Group 1 Elements…
their density increases and their melting point decreases and reactivity increases
Why are Group 1 elements stored in oil?
To make sure they are not exposed to oxygen which they react rapidly with
alkali metal + water =
metal hydroxide + hydrogen
How does lithium react with water?
fizzes steadily and slowly disappears
How does sodium react with water?
melts to form a silvery ball, fizzes vigourously and quickly disappears
How does potassium react with water?
immediately ignites, burns with a lilac flame and very quickly disappears
Explain the trend in reactivity in Group 1 Elements
All atoms in Group 1 have one electron in their outer shell. The easier it is for an atom of a Group 1 Element to lose its outer electron, the more reactive the element is due to forces of attraction between the negatively charged electron and positively charged nucleus.
What do Group 7 elements exist as?
diatomic molecules with weak intermolecular forces
What is fluorine at room temperature?
a pale yellow gas
What is chlorine at room temperature?
a green gas
What is bromine at room temperature?
orange-brown liquid that vapourises easily
What is iodine at room temperature?
a shiny grey-black crystalline solid that sublimes to form a purple vapour
As you go down Group 7…
density increases, melting and boiling points increase, reactivity decreases
Halogens
Group 7 elements which react with metals to produce salts
Explain the trend in reactivity for halogens
All halogens have seven electrons in the outer shell. The easier it is for a halogen atom to gain an outer electron, the more reactive the element is due to forces of attraction between the electrons and the nucleus.
Halide
a compound containing a Group 7 element and another element usually hydrogen or a metal
What happens in a halogen displacement reaction?
a halogen will displace a less reactive halogen from its halide ions in solution
Noble gases
Unreactive elements found in Group 0 of the periodic table
Why are noble gases so unreactive?
They havecomplete outer shells meaning they have no tendency to lose or gain electrons to form ions
What do noble gases exist as?
monoatomic molecules with very weak forces of attraction between them
Why do noble gases have such low boiling points?
Having weak forces of attraction between atoms means these forces are very easily overcome by heating
As you go down Group 0…
attractive forces between atoms get stronger and boiling point increases and density increases
Why do noble gases have very low densities?
Their atoms are very far apart in the gas state
Transition metals
Metals found between Group 2 and Group 3 on the periodic table
What are the properties of transition metals?
shiny when freshly cut, good conductors of electricity, strong, malleable
Compared to alkali metals, transition metals…
are stronger and harder, have higher densities, have have higher melting points (except for mercury)
How do you detect carbon dioxide?
Bubble carbon dioxide through limewater (calcium hydroxide solution) and it will turn cloudy white if there is CO2 [as the reaction between limewater and CO2 produces a white precipitate of calcium carbonate]
How do you detect chlorine?
Hold damp blue litmus paper near a container that holds chlorine and if it is present then the paper will turn red then white
How do you detect hydrogen?
Hold a lighted splint near the mouth of a container of gas and it should ignite with a squeaky poop at the presence of hydrogen
How do you detect oxygen?
Hold a glowing splint near a container of oxygen and if it is present the splint should relight
Flame test colour for lithium ion
red
Flame test colour for sodium ion
yellow
Flame test colour for potassium ion
lilac
Flame test colour for calcium ion
orange-red
Flame test colour for copper ion
green-blue
Hydroxide precipitate test colour for iron(II) ion
green
Hydroxide precipitate test colour for iron(III) ion
orange-brown
Hydroxide precipitate test colour for copper(II) ion
blue
Hydroxide precipitate test colour for calcium ion
white
Hydroxide precipitate test colour for zinc ion
white
How do you detect sulfate ions in a solution?
add a few drops of dilute hydrochloric acid then a few drops of barium chloride solution. if sulfate ions are present, a white precipitate will form
How do you detect carbonate ions?
add a few drops of dilute hydrochloric acid adn if a carbonate is present, bublles of CO2 gas will be produced
How do you detect halide ions?
add a few drops of dilute nitric acid and then a few drops of silver nitrate solution
Halide ion test precipitate colour for chloride ion
white
Halide ion test precipitate colour for bromide ion
cream
Halide ion test precipitate colour for iodide ion
yellow
What are advantages of instrumental methods of analysis?
- Instruments can analyse very small amounts of substances
- Instruments are very accurate
- Instruments can analyse quickly and can run all the time
Theoretical yield equation
(mass of limiting reactant / sum of Mr for limiting reactant) * sum of Mr for products
Percentage yield equation
(actual yield / theoretical yield) * 100
What makes the percentage yield less?
Reactants may react in a different way than expected, reaction may not go to completion, some of the product may be lost when transfering substances between containers.
Atom economy equation
(sum of Mr of desired product / sum of Mr of all products) * 100
Concentration equation
Mass (g) or mol of solute / Volume of solution (dm3)
How much volume does one mole of any substance in the gas state occupy at the same temperature and pressure?
24dm3 (/mol)
Volume of a gas equation
volume (dm3) = mol * 24
Rate of reaction equation
amount of reactant used OR amount of product formed / time taken
Successful collision
a collision of particles that leads to a reaction
A reaction can only happen if…
reactant particles collide with each other and the colliding particles have enough energy to react
As the temperature of a reaction mixture increases…
particles move more quickly so they collide more often and a greater proportion of the collidiong particles have the activation energy
Rate of reaction equation in terms of reaction time
1 / reaction time
The rate of reaction increases as concentration or pressure increases because:
the particles become more crowded, so they collide more often
The rate of reaction increases as surface area increases as…
more particles are available for collisions and collisions are more likely so particles collide more often
Why do catalysts work?
they provide an alternate reaction pathway with a lower activation eneergy
Dynamic equilibrium
forward and backward reaction rates become equal in a closed system
What happens to the equilibrium position when pressure is increased?
shifts to the side with fewer moles of gas
What happens to the equilibrium position when concentration of a substance is increased?
shifts to the side away from the substance where concentration has increased
What happens to the equilibrium position when temperature is increased?
shifts to the side of the endothermic change
symptoms of nitrogen deficiency in plants
poor growth, yellow leaves
Symptoms of phosphorus deficiency in plants
poor root growth, discoloured leaves
Symptoms of potassium deficiency in plants
poor fruit growth, discoloured leaves
Haber process
manufactures ammonia from nitrogen and hydrogen
Haber process equation
N2(g) + 3H2(g) ⇌ 2NH3(g)
Raw materials for the Haber process
air, natural gas, steam
How is nitrogen obtained to be used in the Haber process?
fractional distillation of liquefied air
How is hydrogen obtained to be used in the Haber process?
reacting natural gas with steam
Conditions of the Haber process
200 atmospheres of pressure, 450C and iron catalyst
The forward reaction of the Haber process is
exothermic
What process is used to make ethanol?
Fermentation
Equation for making ethanol
glucose -> carbon dioxide + ethanol
Ore
rock or mineral that contains enough metal to make it economical to extarct it
Metal compound found in malachite ore
copper carbonate
Metal compound found in bauxite ore
aluminium oxide
Metal compound found in haematite
iron(III) oxide
How is copper extracted from a compound?
Reduction with carbon as copper is lower than carbon in the reactivity series
What happens in a blast furnace when extarcting iron?
Coke burns in hot air making carbon dioxide, more coke reduces carbon dioxide to carbon monoxide, carbon monoxide reduces iron(III) oxide to iron at 1500C
How is aluminium oxide electrolysed to extact aluminium?
aluminium oxide is dissolved in molten cryolite and electrolysis takes place to lower the temperature needed to electrolyse
What is the main metal in steel and what are its typical uses?
Iron; buildings, bridges, cars
What are the main metals in duralumin and what are its typical uses?
aluminum and copper; aircraft parts
What are the main metals in solder and what are its typical uses?
tin and copper; joining electrical components
What are the main metals in brass and what are its typical uses?
copper and zinc; musical instruments
What are the main metals in bronze and what are its typical uses?
copper and tin; bells
Why are alloys typically stronger and harder than their individual metals?
Atoms within an alloy are different sizes, making it more difficult for atoms to slide over each other.
Rust equation
iron + oxygen + water -> hydrated iron(III) oxide
How can you reduce rusting?
painting, coating with oil, galvanising (plating with zinc), plating with tin
Sacrificial protection
Coating an iron or steel object with a more reactive metal such as zinc so that the metal corrodes first before the iron
