Science

Questão	Responda
Energy cannot be created or ________. It can only be ___________ from one form to another. (law of conservation of energy)	destroyed transformed
Where does a kettle get its energy from? What is the useful energy from a kettle?	Electric Heat
Current and Voltage is measured in ......	Ampere (Amps) Volts
What are the advantages of using a parallel circuit instead of a series circuit?	If a wire in a parallel circuit breaks the component (bulb) will still work but it wouldn't in a series circuit.
What is a fuse and what how does it work?	A fuse is a safety device that prevents electrocution. When there is too much current flowing the fuse breaks down and melts, disconnecting the circuit.
Which of the following three fruits generates the most electricity naturally and why? Potato Lemon Orange	Lemon, because it has the most citric liquid.
State 4 properties of metals.	Any 4 from: Strong Ductile Malleable Solid Shiny when clean High melting and boiling points Good conductor of heat and electricity Dense Sonorous
State 3 uses of metals	Mercury - thermometers Copper - copper wire for electricity Titanium - airplane bodies
The squeaky pop test is a test for what gas?	Hydrogen
What is needed for rusting to take place?	Water and Oxygen
The process of rusting is called oxidation while the chemical name for rusting is __________ ________	iron oxide
State the 3 ways in which rusting can be prevented.	Greasing or oiling Plating Painting
Metal + Acid = ________ + __________	Salt Hydrogen
Sodium + sulfuric acid = ___ + ___	Sodium sulfate Hydrogen
State the reactivity series from potassium to gold.	Potassium Sodium Calcium Magnesium Aluminium Zinc Iron Lead Copper Silver Gold
Copper compounds are _____	blue
Iron salts are pale green or _____	brown
Aluminium salts are white or colorless while calcium salts are _____	white
Do most metal carbonates dissolve in water?	Yes, they do.
Metal carbonate + acid = _______ + _______ + ________	Salt Carbon dioxide Water
Define bases.	Metal oxides, hydroxides and carbonates that are all alkali.
Copper oxide + HCL = Copper hydroxide + HCL = Copper carbonate + HCL =	Copper chloride + water Copper chloride + water Copper chloride + water + carbon dioxide
In what substance are Nitrogen, Potassium and Phosphate in?	Fertilizers
How can you make large copper sulfate crystals?	By suspension. Suspend a small copper sulfate crystal in a concentrated copper II sulfate solution.
Which salt is formed from the reaction of calcium with nitric acid?	Calcium nitrate
Which gas is formed when a metal carbonate reacts with acid?	carbon dioxide
What is the most reactive metal in the group one metals in the periodic table?	Francium
What is this test for? "Put a burning splint into a tube of the gas ( the gas will explode with a squeaky pop)	Hydrogen gas
Which of these is NOT a sign that a reaction has taken place? a. the substance catches fire b. the substance has changed from a solid to a liquid c. A gas is given off d. There is an explosion	b
In an experiment involving metals and its conduction of electricity which metals would have the greatest voltage? a. copper & copper b. zinc & copper c. zinc & zinc	b
What would you get if copper sulfate and magnesium were reacted together (displacement reaction) and explain?	magnesium sulfate and copper Magnesium will displace copper from its sulfate since it is more reactive than copper.
Iron sulfate + copper =	NO REACTION
Define exothermic and endothermic reactions.	Exothermic reaction - when heat is released Endothermic reaction - when heat is absorbed
What is more reactive, copper or gold?	Copper
Complete combustion of carbon is when carbon is burnt in an excess supply of oxygen producing carbon dioxide and more energy. What is incomplete combustion of carbon?	When carbon is burnt in a limited supply of oxygen producing carbon monoxide and less energy.
If I burn a metal in air will its mass change? If so will it decrease or increase?	Yes the mass will change and it will increase.
What is combustion?	When an element burns in air (to give an oxide).
What needs to happen for this reaction to take place? Aluminium + iron oxide = Aluminium oxide + iron	It needs to be heated
When magnesium is burnt, what happens?	There will be a big white dazzling flame and the magnesium remains will turn white
What sort of reaction is this? Potassium + oxygen = Potassium oxide	Oxidation
Iron is unreactive in ________ and ________ but reacts in _______	Water or Air in any order Acid
Distance is = ? Speed is = ? Time is = ?	Speed * time Distance/time Distance/speed
How long would it take a person to walk 10km if their average speed is 5.4km/h?	10/5.4 = 1.85 hours =1.85*60 =111 minutes
A car is travelling at a constant speed. Compare the forward and the backward forces.	They would be the same.
Give a more scientific term for increasing speed and decreasing speed.	acceleration deceleration
What is the formula for acceleration/deceleration (also include the words final and initial speed/time)?	= final speed - initial speed ___________________________ final time - initial speed
A person first travels for 4 seconds, steadily increasing their speed to 6 m/s from 0 m/s. Then they maintain a constant speed for the next 6 seconds. After they steadily decrease their speed to rest in the last 4 seconds. Calculate the deceleration and acceleration rate (show working).	Acceleration = 6-0/ 4-0 = 1.5 m/s (squared) deceleration = 0-6/ 14-10 = 1.5 m/s (squared)
When there is a balanced force from the left and the right of an object, the object is either at _____ or maintains a _________ speed.	rest constant
A bicyclist streamlines her body. Why?	Because then there is less air resistance acting on her from in front so the force pushing forward would be greater.
A man on a parachute lands safely. Why?	Because the parachute has a large surface area, there is a stronger air resistance force but the gravitational force however is stronger.
Air resistance depends on the size, the _____ and the _____.	Shape Speed
Who discovered force? (Newtons)	Issac Newton
The Normal force (force applied at 90 degrees) per unit area is the definition of what term?	Pressure
Pressure = ? Force = ? Area = ?	Force/Area Pressure*Area Force/Pressure
Pascal is = ?	Newtons/meter squared
Weight, a force, = ?	mass*gravity
10m/s squared is = what force?	Gravity
The ________ surface area the higher the pressure. Max pressure = Force/min Area Min pressure = Force/max Area	smaller
Why do knives have a sharp edge?	Because they are used to cut through something and if they have a small surface area at their point then less force can be applied and there will still be a high pressure.
Why does a balloon expand (force)?	When air is blown into a balloon a force is exerted on the molecules causing them to push the balloon walls thus forcing the balloon to expand.
The ________ the altitude the ________ the atmospheric pressure.	lower - higher OR higher - lower
Why do tractors have large tyres?	This helps because the tractor would not get stuck in the soil since there is less pressure applied onto the soil because of the large surface area of the tyres
Does pressure in liquids increase or decrease with depth?	Increases with depth
When I put a beaker on a strip of water nothing really happens but when I put a burning paper in the beaker then put it on a strip of water, the water outside of the beaker pushes the water inside the beaker. Why?	At first the pressure is the same in and out the beaker but when the burning paper is put in the beaker oxygen is being used up thus creating a lower pressure inside the beaker and a higher pressure outside. The higher pressure outside pushes the water into the beaker.
Define a moment	a turning effect of a force at a fixed point (pivot)
The larger the perpendicular distance form the pivot point and the bigger the force the ______ the turning point.	larger
Moment of a force = ? Unit for moment = ?	Force * perpendicular distance form pivot Newton meter (Nm)
A large force * a small distance = a ________ force * a _________ distance	small large
The force is 2N The perpendicular distance is 0.4m. What is the moment?	2*0.4 = 0.8Nm
Clockwise moment = _________ moment Balanced or not moving object	Anti-clockwise
The larger the perpendicular distance from the pivot, the _____ force needed.	less
Why should you grip the handle bars of a bicycle at the ends?	Because that would mean less force will be needed to turn or twist since the perpendicular distance is large so less force needed.
Where is the center of gravity for uniform objects like a meter ruler?	The center of the body
What should I do if I want to stabilize an object? State the two factors.	Put the object on a large surface area and make sure the center of gravity of the object is closer to the ground.
How can an object be in an unstable equilibrium?	When its center of mass / gravity is directly above the pivot point.
Pressure in _________ = depth * density * gravity	liquids
When a car passes by, a person was pushed slightly towards the car. Why?	A car runs by the engine which uses oxygen, so when the car passes by the person the oxygen on one side of him/her is taken in creating a low pressure thus making the higher pressure on his/her other side push the person towards the car.
What does hydraulic fluid do?	Hydraulic fluid is used in car brakes and multiplies the force and area but the pressure will be the same as the beginning. e,g 10/2 = 5 ALSO 1000/200 = 5

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	Criado por pranathi_shekar mais de 8 anos atrás