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A chemical reaction takes place when water is put to a boil passing electricity through a heater immersed in the water.
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during a chemical reaction, energy:
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is taken in
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is given out
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remains the same
Frage 3
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When reactants are mixed,energy is used for ______ the molecules of the reactants into ________
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the atoms ____ themselves to form the products
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rearrange
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recombine
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break
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divide
Frage 5
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If the amount of energy required to break the atoms up is 250 and the the amount of energy released when atoms recombine is 300,what is the amount of energy exchanged with the surroundings?
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A chemical reaction is used to describe a chemical equation
Frage 7
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No atoms are created or destroyed in a chemical reaction
Frage 8
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At room temperature gold is _____,water is _____ and oxygen is ________
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solid...liquid...gas
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gas...liquid...solid
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liquid....gas...solid
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liquid...solid...gas
Frage 9
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Atoms and molecules are said to be in a constant______
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motion
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arrangement
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order
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state
Frage 10
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in a solid the atoms are:
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packed closely together in a regular pattern
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move around eachother
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held and spun around in fixed positions
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have weak attractive forces
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have strong attractive forces
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have a definite shape and volume
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does not have a fixed volume
Frage 11
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If a solid is heated the particles_____________________________________________________
Frage 12
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in a liquid the atoms are arranged in a fixed pattern
Frage 13
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liquids can flow because:
Frage 14
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in a gas the atoms are:
Frage 15
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solid to gas is the process of ________
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boiling
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sublimation
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freezing
Frage 16
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electricity is produced by flow of
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electric charges
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electric current
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atoms
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energy
Frage 17
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conventional current is the flow of electric charges from the _______ end to the ________ end
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positive.....to negative
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negative.....to positive
Frage 18
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Electric current is defined as:
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the rate of flow of electric charges
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the rate of flow of electric current
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the rate of flow of electricity
Frage 19
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the SI unit for electricity is ampere (A)
Frage 20
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electric currents are measured by
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ammeters
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voltmeters
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generators
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cellphones
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Ammeters must be connected in parallel
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ammeter may get damaged if
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electric circuits can be divided into two main categories:
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An electric circuit is a path along which electric charges move
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A series circuit forms a double loop
Frage 26
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the current flowing through each electrical component in a series circuit is _____
Frage 27
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disadvantage of series circuit is that there is less current flowing in each branch rather than that flowing out of the circuit
Frage 28
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what is a parallel circuit?
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A circuit that splits into two or more branches
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A circuit that forms a single loop
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A circuit with multiple batteries
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A colorful circuit with balloons
Frage 29
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Advantage of Parallel circuit is that the current flowing through each component is same.
Frage 30
Frage 31
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the force needed to push electric charges round a circuit is supplied by:
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a battery
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an electric cell
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a bulb
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a toy
Frage 32
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the amount of energy supplied by a source of electrical energy to each unit of electric charge is called ________
Frage 33
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If more electric cells are connected in series,a ________ voltage will be obtained
Frage 34
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Electrical energy is converted into light and heat when flowing through a bulb
Frage 35
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SI unit of voltage is ______
Frage 36
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The voltage of a source of electrical energy is called
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electromotive force
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potential difference
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energy
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cupcake
Frage 37
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Resistors can only be added in series.
Frage 38
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which of the following have heating elements inside them?
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hair dryer
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cellphone
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cranes
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toaster
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iron
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magnet
Frage 39
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The heating element is usually made up of ________________
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nichrome wire
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conductor
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plastic
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coiled coil
Frage 40
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In electro-plating the plating metal is connected to the __________ terminal
Frage 41
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which of the following are uses of electromagnets
Frage 42
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improper use of electricity can result in:
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electrocutions
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electric fires
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electric shocks
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dehydration
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high blood pressure
Frage 43
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The consumer unit consists of damp conditions,main switch and electric bells.
Frage 44
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some dangerous situations of using electricity are:
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damp conditions
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damaged insulation
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over-loading
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sleeping near it
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sitting on it
Frage 45
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If it takes a 4kW kettle 10 minutes to boil the water in it,how much energy is used?
Calculate the cost of electricity if each unit costs 21 cents.
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2/3 kW and 14 cents
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1/3 kW and 6 cents
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1/2 kW and 21 cents