Flashcards in Seperate chemistry 1 Deck (48):
Where are the transition metals located on the periodic table?
In the middle.
What are the properties of the transition metals?
-High melting point
-Typical metal properties
Transition metals and their compounds make good what?
What is a catalyst?
It speeds up the rate of reaction without being changed or used up itself.
The compounds of transition metals tend to be what?
What are alloys?
They are made by adding another element to a metal - that could be metal or non-metal.
Why are alloys used rather than pure metals?
Pure metals have a regular arrangement of identical ions, the layers of ions can slide over each other. An alloy has different sized atoms making it more difficult for the layers to slide, so alloys are stronger.
Alloys of iron are called what?
Why is iron alloyed with other metals to create steels?
It will rust fairly quickly on its own. Steel is also stronger.
What are aluminium alloys used for and why?
It is used for aircraft manufacture, as it has a low density.
What are gold alloys used for and why?
Jewellery- The purer the gold the higher the carat.
How is magnalium made and what is it used for?
Aluminium + Magnesium: Used to make parts of cars and aeroplanes. Magnalium with a higher magnesium content is used in fireworks.
Metals can corrode in the presence of what?
Oxygen and water to form metal oxides.
Oxidation of metals results in what?
What is sacrificial protection?
This involves placing a more reactive metal with the iron. The water and oxygen react with this `sacrificial' metal instead of the object you are protecting.
What is galvanising?
An example of sacrificial protection. A coat of zinc is put onto an iron object to prevent rusting.
What is electroplating?
This is when the surface of a metal is coated with another metal using electrolysis.
How do you electroplate an object?
The cathode is the object you're going to electroplate the anode is the bar of metal you're using for the plating. Your electrolyte is a solution containing the metal ions of the metal you're plating.
How is electroplating useful?
-It stops metals reacting/corroding
-It improves the appearance of Jewellery and makes it look shiny
What is titration?
Titration allows you to find the exact amount of acid needed to neutralise a given quantity of alkali or vice versa.
Core Practical: Carry out an accurate acid-alkali titration, using burette, pipette and a suitable indicator
-Using a pipette, measure out a set volume of the alkali into a flask, Add a few drops of an indicator
-Fill a burette with a known concentration of acid
-Use the burette to add the acid to the alkali a bit at a time. Swirl the flask regularly.
-The indicator changes colour when all the alkali has been neutralised
-Record volume of acid used to neutralise alkali
-Repeat and take mean of results
The concentration of a solution can be measured in what?
moles per dm³.
What is the formula for concentration in mol dm³?
Concentration = number of moles ÷ volume of solution
What is the formula for percentage yield?
Percentage yield = actual yield
What is the theoretical yield of a reaction?
The mass of product you'd make if all the reactants were converted to products.
In real life, you never get 100% yield, why?
-Practical losses: You always lose a bit when you transfer chemicals between containers
-Unwanted reaction: Caused by impurities/change in reaction conditions
What is the atom economy of a reaction?
It tells you what percentage of the mass of the reactants has been converted into your desired product when manufacturing a chemical.
What is the formula for atom economy?
Atom Economy = total Mᵣ of desired products
total Mᵣ of all products
A higher atom economy is better for what?
Profits and the environment.
Explain why a particular reaction pathway is chosen to produce a specified product.
To give useful `by-products'.
How can you reach equilibrium faster?
High temperature, concentration and pressure. As well as the use of a catalyst.
The three main essential elements in fertilisers are what?
Nitrogen, phosphorus and potassium.
What are the benefits of using ammonia fertilisers in comparison to traditional fertilisers?
You can control the composition of the chemicals in them. They are also soluble, so all the chemicals can be dissolved into the soil to reach the plants.
Ammonia can be reacted with oxygen and water to make what?
Ammonia and nitric acids react together to produce what?
The salt ammonium nitrate - a fertiliser.
How do you prepare Ammonium sulphate in a lab?
-Add a few drops of methyl orange indicator to the ammonia - it'll turn yellow
-Slowly add the dilute sulphuric acid from the burette into the ammonia, until the yellow changes red, this means the ammonia has been neutralised and you've got ammonium sulphate solution.
-To get pure ammonium sulphate crystals, you must remove the methyl orange indicator. Note how much sulphuric acid it took to neutralise the ammonia, then repeat the titration using the volume of acid, but no indicator.
-To get crystals gently evaporate solutions, leave it to crystallise, then filter out the crystals and leave them to dry.
What is molar volume?
The volume occupied by one mole of a gas.
What are the units of molar volume?
What is the formula for molar volume?
molar volume = gas volume ÷ number of moles
What is Avogadro's law?
It states that under the same conditions, the same number of moles of different gases all occupy the same volume.
One mole of any gas always occupies how much space?
What is RTP?
RTP = 20°C and 1 atmosphere.
What is the equation triangle for volume, moles and 24 dm³?
Moles x 24
What is a fuel cell?
It is an electrical cell that's supplied with a fuel and oxygen and uses energy from the reaction between them to produce electrical energy efficiently.
Chemical cells produce what?
A voltage across the cell, until all of one of the reactants has been used up.
What happens in a hydrogen-oxygen fuel cell?
You can produce a voltage by reacting hydrogen and oxygen. The product of the reaction is water.
What are the benefits of hydrogen-oxygen fuel cells?
-No conventional pollutants
- Less stages means there are less places for energy to be lost as heat