RPs paper 3 and 4 Flashcards
True or false – the work done to stretch a spring is equal to the elastic potential energy stored in the spring
True – unless the limit of proportionality is exceeded
What does a linear force-extension graph mean about the force and extension?
They are directly proportional
What is the equation that links extension, force and spring constant?
Spring constant = Force / Extension
State Hooke’s Law.
Force and extension are directly proportional
What are the units for spring constant?
N/m
What is the difference between elastic and inelastic deformation?
Elastic – object returns to original size when forces are removed
What is elastic limit?
The point at which an object is deformed inelastically
How can we identify the elastic limit on a graph?
When the line of best fit starts to curve
What is the dependent variable when you investigate force and extension of a spring?
Extension of the spring
Give one control variable when investigating Hooke’s law.
Material of spring, where the length of spring is measured from and to
What are the SI units for extension?
Meters (m)
What is the equation that links gravitational field strength, mass and weight?
Weight = Mass x G.F.S
What is the equation that links elastic potential energy, extension and spring constant?
Ee = 0.5 x spring constant x extension2
Rearrange the equation in Q5 to make spring constant the subject.
Spring constant = Ee / (0.5 x extension2)
What are the units for weight?
Newtons, N
True or false? Elastic bands obey Hooke’s law.
False
What is inertia?
The tendency of an object to remain in its current state of motion
What is a vector quantity?
A quantity with both magnitude and direction
If the resultant force acting on an object is zero, what do you know about its velocity?
Velocity is constant
What is the equation that links force, mass and acceleration?
Force = Mass x Acceleration
What is the resultant force acting on an object falling at terminal velocity?
Zero
How is increasing deceleration shown on a V-T graph?
Downwards curve which gets steeper
What is the equation to calculate the acceleration?
Change in velocity / Time
What is a scalar quantity?
Quantity with magnitude only
Select the correct word to complete Newton’s second law: An object’s________________ depends on the _____________________ acting on the object and the ______________ of the object.
Acceleration, Forces, Mass
What is the equation that links acceleration, force and mass?
Force = Mass x Acceleration
What is the equation for calculating speed?
Speed = Distance / Time
What do the letters in this equation mean? v2 –u2 = 2as
v – final velocity, u – initial velocity, a – acceleration, s - displacement
What is the relationship between force and extension?
Directly proportional
What is the relationship between mass and extension?
Inversely proportional
What is the equation that links potential difference, current and resistance?
Potential difference = Current x Resistance
What are the units for resistance?
Ohms
True or false – a diode has a very high resistance in one direction.
True
What is the relationship between potential difference and current for an ohmic conductor?
Directly proportional
What is the unit for charge flow?
Coulombs, C
Describe the current in a single closed loop.
The same anywhere in the circuit
State Ohm’s Law.
If resistance is constant, potential difference and current are directly proportional
What do we also call potential difference?
Voltage
State the equation that links current, potential difference and resistance.
Potential difference = Current x Resistance
State the equation that links charge, current and time.
Current = Charge / Time
Describe the IV graph for a resistor.
Directly proportional- straight line through 0.
Describe the IV graph for a filament bulb.
S Shaped curve
Describe the IV graph for a dioide.
Line only in one half of the graph
Where in a circuit should an ammeter be placed?
In series
Where in a circuit should a voltmeter be placed?
In parallel
What is an ohmic conductor?
A conductor which obeys Ohm’s law
Name a component that behaves as a non-ohmic conductor.
Filament lamp, diode
What is a diode?
A component which has a high resistance in one direction
Describe the IV graph of a filament lamp.
An S-curve which passes through the origin
Explain the IV graph of a filament lamp.
As current increases, so does resistance meaning it is more difficult for current to flow
Describe the relationship between temperature and resistance of a thermistor.
As temperature increases, resistance decreases
Describe the relationship between temperature and resistance of a LDR.
As light increases, resistance decreases
Describe the relationship between length of wire and resistance.
As length of wire increases, resistance increases
How do you find the total resistance of a series circuit?
Add up the individual resistance of all the components
What is an ammeter?
Measures current
How is an ammeter placed in a circuit?
Series
What is a voltmeter?
Measures voltage/ potential difference
How is a voltmeter placed in a circuit?
Parallel
What is a base?
A substance with a pH of more than 7
What type of salt is made when nitric acid is used?
Nitrate
What is the general word equation for neutralisation?
Acid + Base (Alkali) à Salt + Water
What is an alkali?
A soluble base
What ion do all acids contain?
H+
What is the pH range of an acid?
1 to 6
What is the pH of a neutral substance?
7
What is the pH range of an alkali?
8 to 14
What type of salt is formed from Hydrochloric acid?
Chloride salt
What type of salt is formed from Nitric acid?
Nitrate salt
What type of salt is formed from Sulphuric acid?
Sulphate salt
What is an exothermic reaction?
A reaction that releases energyto the surroundings
Give an example of an exothermic reaction.
Combustion, neutralisation
What is an endothermic reaction?
A reaction that absorbs energy from the surroundings
Give an example of an exothermic reaction.
Photosynthesis
What equipment can be used to measure temperature?
Thermometer
In an exothermic reaction, what has more energy- reactants or products?
Reactants
In an endothermic reaction, what has more energy- reactants or products?
Products
Name 3 factors that affect the rate of a chemical reaction.
Temperature, pressure, concentration, surface area, catalyst
How can you tell that a reaction has finished from a rate graph?
The line of best fit will plateau/flatten
Define the term activation energy.
Energy needed to start a reaction
True or false: “Reactants are produced during a chemical reaction”.
False
What are the signs that a chemical reaction is occurring?
Colour change, bubbles/ fizzing, temperature change, new product made
What is a catalyst?
Something which speeds up a reaction, without being used up
How does a catalyst speed up a reaction?
Lowering the activation energy
What is the difference between an exothermic and endothermic reaction?
Exothermic releases energy, endothermic absorbs energy
What factors increase the rate of a chemical reaction?
Temperature, pressure, concentration, surface area, catalyst
Give the equation for calculating the rate of a reaction.
Reactant used / Time or Product formed / Time
What is a precipitate?
A solid formed in a liquid
Which gas is tested for using a lit splint, which makes a squeaky pop?
Hydrogen
How does a catalyst speed up a reaction?
Lowering activation energy
Why does the mass of some reactions appear to increase?
One of the reactants is a gas, whose mass has not been accounted for
Describe one way we can measure the volume of gas produced during a reaction.
Gas syringe, upturned measuring cylinder in water/ displacement
Give one precaution needed when using hydrochloric acid.
Goggles – to protect eyes
True or false? “The volume of sodium thiosulphate is the dependent variable when measuring turbidity.”
False – it is the independent variable
What is the name of the area on an enzyme with a unique 3D shape?
Active site
Define the term denature.
When the active site changes shape and no longer fits with the substrate
What is the optimum temperature that enzymes work at in the human body?
37
True or False: “Increasing the concentration of a product increases the rate of a chemical reaction.”
False
How can you measure the rate of a chemical reaction?
Reactant used or product made divided by time
How does increasing surface area increase the rate of a reaction?
More reactant particles are exposed, so more frequent collisions
What are the 2 products of a neutralisation reaction?
Salt and water
What equipment is required to crystalize a salt solution?
Evaporating basin, heat source
What is the name of the enzyme that breaks down starch into glucose?
Amylase
Name the chemical used to test for the presence of starch.
Iodine
What is an enzyme made from?
Protein
What can happen to an enzyme if the pH becomes too extreme?
Denature/ active site will change shape
Name 2 factors that can increase the rate of a chemical reaction.
Temperature, pressure, catalyst concentration, surface area
Name 2 signs that a chemical reaction is occurring.
Gas (bubbles/fizzing), colour or temperature change, new products
Is energy taken in or given out when bonds are made?
Given out
True or False: “An exothermic reaction takes in energy from the surroundings.”
False – it releases energy
What is the positive electrode called?
Anode
What is the negative electrode called?
Cathode
Which of these is NOT attracted to the negative electrode?
Halide
What are the two possible products at the positive electrode?
Halogen or oxygen
Why are electrodes made of graphite?
Unreactive
Why must an electrolyte be molten or in solution?
So the ions can move
What symbol shows that an electrolyte is a solution?
(aq)
What type of power supply is used for electrolysis
DC
What does electrolysis mean?
Breaking something down using electricity
What is the difference between an atom and an ion?
Atoms are neutral, ions are charged
What is the positive electrode called?
Anode
What moves towards the positive electrode?
Negative ions
What is the negative electrode called?
Cathode
Why would electrolysis not occur if electrodes are touching?
They would conduct the electricity from one to the other
What is an electrolyte?
A molten or dissolved ionic compound
Why are the products of electrolysis of aqueous sodium chloride and copper chloride different?
Sodium is more reactive than hydrogen, whereas copper is less reactive
