Paper 1: Section 5 - Separate chemistry 1 Flashcards
What is a transition metal?
A metal located in between group 2 and 3 and has brightly coloured compounds.
Most metals are _______ metals. They include iron and other metals used in construction, like ____. The transition metals are placed in the ______ part of the periodic table.
- transition
- gold
- central
What are the typical properties of most transition metals?
. High melting points
. High densities
. Form coloured compounds
. They (and their compounds) can act as catalysts
Give an example of a transition metal that has the typical properties of a transition metal:
Iron:
. Melting point= 1538°C
. Density= 7.87 g/cm3
. Coloured compounds:
Fe(OH)2 Pale green
Fe(OH)3 Orange-brown
Fe2O3 Red-brown
. Acts as a catalyst for: The Haber process
What is corrosion?
When a metal is slowly damaged or destroyed by a chemical process.
What is the corrosion of a metal cause by?
Redox reactions
What is a redox reaction?
The metal loses electrons, so its oxidised. When oxygen reacts with the metal, it gains electrons.
What is the process of rusting?
The process in which iron or steel is corroded.
When does rusting occur?
When iron or steel is in contact with both oxygen and water.
Is iron oxidised or reduced when it forms rust? Why?
Iron is oxidised because it gains oxygen during rusting.
What storing methods can be used to prevent rusting?
. Storing the metal in an atmosphere of unreactive nitrogen or argon will exclude oxygen.
. Storing the metal with a desiccant such as calcium chloride can exclude water.
What physical barriers can be used to prevent rusting?
. painting
. oiling and greasing
. coating with plastic
Electroplating: Using _________ to deposit a thin layer of _____ onto another metal, usually to improve its appearance or _______ resistance.
- electrolysis
- metal
- corrosion
Sacrificial protection: Iron can be protected from rusting if it is in contact with a more _______ metal. The more reactive metal oxidises more ______ than iron, so it ‘sacrifices’ itself while the iron does not ____. Once the sacrificial metal has ________ away, it can simply be replaced.
- reactive
- readily
- rust
- corroded
Galvanising: This is the proccess where iron is coated in ____. The layer stops oxygen and _____ reaching the iron. Zinc is ____ reactive than iron, so it also acts as a __________ metal.
- zinc
- water
- more
- sacrificial
What is an alloy?
An alloy is a mixture of two or more elements, at least one of which is a metal.
Solid metals have a regular ______ structure. When a _____ is applied to a metal, layers of atoms can ____ past each other. The more difficult it is for the layers to move, the more ____ is needed and the ______ the metal.
- lattice
- force
- move
- force
- stronger
Why is iron alloyed with other metals to produce alloy steels?
Alloy steels are produced by mixing iron with one or more other metals because each one is useful for different things.
What are the different properties of alloy steels, depending on their composition?
Mild steel- Is malleable and ductile
Tool steel- Is hard and resistant to high temperatures
Stainless steel- Hard and resistant to rusting
Gold is a very soft and _______ metal. It is also very unreactive, so it resists _______ and stays shiny.
The visors on space _______ are coated with a layer of gold as it’s thin enough for the astronaut to see through but thick enough to ______ sunlight.
The gold used for jewellery is gold _______ with other metals, often silver, copper and zinc. This makes the jewellery much stronger while keeping its ability to stay ______.
- malleable
- corrosion
- helmets
- reflect
- alloyed
- shiny
Bronze is an alloy of ______ and tin. Nowadays, bronze is used to make _______, bells and coins seeing as its highly ductile, exhibits ___ friction and upon exposure to air, bronze ______ on its outer layer (protecting the interior from further corrosion).
Brass is an alloy of copper and ____, and is used to make musical instruments, ____ ______, locks and ____.
- copper
- statues
- low
- oxidizes
- zinc
- door knobs
- taps
Aluminium is relatively lightweight as it has a low _______. Its surface is protected by a layer of aluminium ______, allowing the metal to resist corrosion. Aluminium foil is used in the home for wrapping and storing food because it does not ______ to substances in food, like _____. It is _________, so it is easily folded into shape around the food.
- density
- oxide
- react
- water
- malleable
What is magnalium?
Magnalium is an alloy of aluminium and magnesium. It is stronger than aluminium alone but still has a low density. It is used to make aircraft parts.
How do you calculate the concentration (in mol/dm3) of a solution?
Concentration mol/dm3= amount of solute in moles/ volume of solution in dm3
How do you convert volume from cm3 to dm3?
Divide by 1000 to convert from cm3 to dm3.
How do you convert concentration in dm3 into mol g dm3?
To convert from mol/dm3 to g/dm3, multiply by the relative formula mass.
Titrations are a procedure in which two solutions react in a known ____. If the ___________ of one solution is known (as well as both the _______ are measured), the concentration of the other solution can be __________.
- ratio
- concentration
- volumes
- determined
How do you calculate the concentration of unknown solution?
Concentration of unknown solution = (volume of known solution ÷ volume of unknown solution) × concentration of known solution
What is the definition of the theoretical yield? How is it calculated?
The maximum possible mass of a product that a chemical reaction can make. It is calculated using molar ratios.
What is the definition of the actual yield?
The mass of a product that a chemical reaction makes in real life. It is usually less than the theoretical yield, for a number of reasons.
Why is the actual yield of a reaction usually less than the theoretical yield?
. Some product may be lost when the products are removed from the reaction mixture
. There might be side reactions – unwanted reactions that compete with the desired one
. The reactions may be incomplete
How do you calculate the percentage yield of a reaction from the actual
yield and the theoretical yield?
Percentage yield= actual yield/ theoretical yield x 100
How do you calculate the theoretical yield?
Moles= mass (g)/ Mr
What is the definition of the actual yield?
The mass of a product that a chemical reaction makes in real life.
The atom economy of a reaction is a measure of how many ________ atoms form a desired product. It is important for _________ development and for economic reasons to use reactions with ____ atom economy.
- reactant
- sustainable
- high