Science Test 1 Flashcards
Materials, Energy Changes in Chemical Reactions, Electricity and Magnetism
What is the word equation for metal and oxygen?
Metal + oxygen —> Metal oxide
What is the word equation for metal and water?
Metal + Water —> Metal hydroxide + hydrogen
What is a displacement reaction?
A more reactive element can displace a less reactive element out of its compound during a chemical reaction.
Explain a displacement reaction.
A more reactive metal will displace or push out a less reactive metal from its compound in a displacement reaction. The less reactive metal is left uncombined after the reaction. It is no longer chemically bonded to any other
elements.
How do metals get extracted from their ores?
Metals more reactive than carbon will be extracted by electrolysis.
Metals less reactive than carbon can be extracted by reduction from carbon by displacing the metal compound.
Metals less reactive than hydrogen can be found natively.
What is a polymer?
A polymer is a large molecule which is made when hundreds of monomers join together to form large chains.
What is plastic?
Plastic is a synthetic polymer which can be shaped by heat or pressure.
What is the process of turning monomers into polymers?
Addition polymerisation
What is a monomer?
An alkene that is a class of hydrocarbons which contains a carbon-carbon double covalent bond.
What is the simplest alkene?
Ethene
What is a covalent bond?
A bond between two non-metals
What are the two main ways to extract metals from their ores?
Carbon Reduction and electrolysis
How can you find metals which are less reactive than hydrogen?
Natively
What type of reaction is thermal decomposition?
Endothermic
What is thermal decomposition?
The breaking of a compound to form 2 or more products using heat.
What does Calcium Carbonate decompose thermally into?
Calcium Oxide and Carbon Dioxide
What is a catalyst?
A catalyst is a substance that speeds up a reaction without getting used up in the reaction
Give an industrial use of a catalyst
The HABER Process - Iron is used as a catalyst to speed up the manufacture of ammonia
In terms of particle theory, how do Catalysts work?
Catalysts absorb molecules that stretch bonds brings reacting parts of molecules right next to each other
What is an exothermic reaction?
Energy exits from the system to the surroundings this causes an increase in temperature - More bonds are made than broken
What is an endothermic reaction?
Energy enters from the surroundings to the system this causes cooling - More bonds are broken than made
What is a chemical reaction?
Atoms are rearranged in a chemical reaction, but the number of atoms does not change
What changes of state are endothermic?
Melting and Boiling are endothermic
Which changes of state are exothermic?
Freezing and condensation
Which charges attract?
Opposites
What is static electricity?
When friction is created between two insulators, and causes them to attract, where one insulator is positive and the other is negative and they attract.
What is transferred in static electricity?
Electrons
What type of force is Magnetism?
Non-contact
What is permanent magnet?
A magnet that always causes a force on other magnets and magnetic materials
Name the two key features of permanent magnets
- It produces its own magnetic field
- The magnet cannot be turned on and off
What is an induced magnet?
An induced magnet is only a magnet when it is placed in a magnetic field, its magnetism is lost when it is not placed in a magnetic field
What are the only magnetic elements?
Nickel, Cobalt, Iron
What do closer lines in a magnetic field mean?
The magnetic field is stronger
How does a compass always point north?
A compass always points north, because it attracts the north of Earths magnetic field with the South Pole of the magnet in the compass
What is an electromagnet?
An electromagnet is when a current flows along a wire causing a magnetic field around the wire
What is a solenoid?
A Coil of wire
What 3 things increase the strength of an electromagnet?
Increase the current, Increase the number of coils, Insert an iron core
Do solenoids and bar magnets have identical magnetic fields?
Yes
What is a conductor?
A material that lets electricity pass through. All metals are conductors
Do conductors have low or high resistance?
Low
Do insulators have a low or high resistance?
High
What is an insulator?
An insulator is a material that does not let electricity pass through?
What is electric current?
The flow of electrons around a circuit, the electrons can only flow in a closed circuit
Why do metals conduct electricity?
Because of their free delocalised electrons, which collide and conduct both heat and electricity.
Why do insulators not conduct electricity?
Because the electrons are stuck in place
What is current?
How many electrons pass in one second.
What is the unit for current?
Amps (A)
What do we measure instead of the no of electrons?
Charge
What is a series circuit?
Components are connected in one continuous loop.
What is the unit for charge?
Coulombs
What if one bulb breaks in a series circuit?
The other will go out
What is a parallel circuit?
Components are connected on separate branches
What will the current be at any point of a series circuit?
The same
What happens to the current in a parallel circuit?
The current splits down the branch
What is the test for starch?
Add iodine solution to the food and if a colour change of blue-black occurs then it contains starch
What is the test for protein?
Biuret’s solution and wait for a purple colour change to occur
What is the test for reducing sugar?
Put the food in a boiling tube and add Benedict’s solution and place in a hot water bath, and if it has a colour change of green/yellow/green then it contains reducing sugar.
What is the test for lipids?
The reagent for lipids are a white emulsion
What is a vitamin?
It is a substance needed for bodily functions that cannot be synthesised by the body
What is a mineral?
An ion that is needed for bodily functions that can be synthesised by the body
