A chemical reaction takes place when water is put to a boil passing electricity through a heater immersed in the water.
during a chemical reaction, energy:
is taken in
is given out
remains the same
When reactants are mixed,energy is used for ______ the molecules of the reactants into ________
breaking up.....into atoms
combining...into compounds
absorbing....into atoms
the atoms ____ themselves to form the products
rearrange
recombine
break
divide
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?
50
550
300
250
A chemical reaction is used to describe a chemical equation
No atoms are created or destroyed in a chemical reaction
At room temperature gold is _____,water is _____ and oxygen is ________
solid...liquid...gas
gas...liquid...solid
liquid....gas...solid
liquid...solid...gas
Atoms and molecules are said to be in a constant______
motion
arrangement
order
state
in a solid the atoms are:
packed closely together in a regular pattern
move around eachother
held and spun around in fixed positions
have weak attractive forces
have strong attractive forces
have a definite shape and volume
does not have a fixed volume
If a solid is heated the particles_____________________________________________________
gain energy and start to vibrate more
slow down
break down
combine
in a liquid the atoms are arranged in a fixed pattern
liquids can flow because:
they have fixed atoms
they can move around one another
they are closely packed
they have strong attractive forces
in a gas the atoms are:
widely spaced and move freely
able to fill up any container quickly
slow
combined together
solid to gas is the process of ________
boiling
sublimation
freezing
electricity is produced by flow of
electric charges
electric current
atoms
energy
conventional current is the flow of electric charges from the _______ end to the ________ end
positive.....to negative
negative.....to positive
Electric current is defined as:
the rate of flow of electric charges
the rate of flow of electric current
the rate of flow of electricity
the SI unit for electricity is ampere (A)
electric currents are measured by
ammeters
voltmeters
generators
cellphones
Ammeters must be connected in parallel
ammeter may get damaged if
connected the other way round
connected in parallel
connected from positive to negative
connected in series
electric circuits can be divided into two main categories:
series and parallel
ammeter and voltmeter
electric charges and electric current
An electric circuit is a path along which electric charges move
A series circuit forms a double loop
the current flowing through each electrical component in a series circuit is _____
same
different
opposite
disadvantage of series circuit is that there is less current flowing in each branch rather than that flowing out of the circuit
what is a parallel circuit?
A circuit that splits into two or more branches
A circuit that forms a single loop
A circuit with multiple batteries
A colorful circuit with balloons
Advantage of Parallel circuit is that the current flowing through each component is same.
A source is
a battery
component from the where the current starts
wires and bulbs in a circuit are a part of the source
the force needed to push electric charges round a circuit is supplied by:
an electric cell
a bulb
a toy
the amount of energy supplied by a source of electrical energy to each unit of electric charge is called ________
voltage
power
Resistance
If more electric cells are connected in series,a ________ voltage will be obtained
higher
lower
decreased
Electrical energy is converted into light and heat when flowing through a bulb
SI unit of voltage is ______
volt (V)
Joules
ohm
The voltage of a source of electrical energy is called
electromotive force
potential difference
cupcake
Resistors can only be added in series.
which of the following have heating elements inside them?
hair dryer
cellphone
cranes
toaster
iron
magnet
The heating element is usually made up of ________________
nichrome wire
conductor
plastic
coiled coil
In electro-plating the plating metal is connected to the __________ terminal
positive
negative
which of the following are uses of electromagnets
used in scrapyards
check thickness of paint in a car
televisions
kettle
remove splinters from body
improper use of electricity can result in:
electrocutions
electric fires
electric shocks
dehydration
high blood pressure
The consumer unit consists of damp conditions,main switch and electric bells.
some dangerous situations of using electricity are:
damp conditions
damaged insulation
over-loading
sleeping near it
sitting on it
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.
2/3 kW and 14 cents
1/3 kW and 6 cents
1/2 kW and 21 cents