Flashcards
8th Grade Physical Science Final Review
Cards in this deck (30)
- 1In making a cake, which process involves a chemical change? a. mixing ingredients for the batter b. slicing strawberries for the topping c. spreading frosting on the cake d. baking the batter to form the cakeA chemical change means a NEW substance was created.
That means that the only choice that is a chemical change is BAKING BATTER TO MAKE CAKE. - 2The diagram below shows the geometric structure of a molecule of water (H2O). What do the symbols (Black Circles) and (Grey Circle) represent in the model? a. genetic material b. cells c. chemical bonds d. atomsThe black and grey circles represent ATOMS
- 3The law of conservation of mass can be demonstrated by a chemical reaction. Which of the following models of a chemical reaction best represents the law of conservation of mass?The # of atoms on the reactants side (left side of arrow) has to be the same as the # of atoms on the product side (right side of arrow). This means the correct answer D...there are 2 white atoms and 1 grey atoms on each side of the arrow.
- 4Which one of the following pictures shows the object that is the most dense?The more tightly packed the atoms are, the denser the object. This means the most dense picture would be B.
- 5A baseball strikes the roof of a car and dents it. The paint on the roof begins to crack and chip, exposing the metal. The exposed metal on the roof rusts, eventually causing a small hole in the roof. Which event is NOT a physical change? a. the paint cracks and chips b. the exposed metal rusts c. the rook of the car dents d. the baseball strikes the roofA physical change just changes physical properties like size and shape.
A chemical change creates a NEW substance and can not be reversed.
The only new substance formed is rust...this means the correct answer is b. - 6Heat will continue to transfer between two areas or objects until a. both areas/objects are the same temperature b. the melting point is reached c. all heat energy is lost to the air d. the colder object absorbs all of the heat energyHeat will transfer until both areas/objects are the SAME temperature.
- 7Which of the following is formed when two elements combine chemically? a. an electron b. a atom c. a compound d. a mixtureA compound
A compound is formed when two or more elements form a chemical bond. - 8What is the smallest unit of a chemical compound that still has the properties of that compound? a. a nucleus b. a molecule c. an element d. an atomA molecule AT LEAST 2 atoms (elements) bonded together. This is the smallest unit of a chemical compound.
- 9A student is given a sample of an unknown liquid to test in the laboratory. The student thinks that the liquid is water. Which of the following physical properties of the sample is most helpful to determine if the liquid is water? a. the color of the liquid b. the mass of the liquid c. the volume of the liquid d. the boiling point of the liquidBoiling Point
Water boils at 212 degrees. Other liquids with the same, color, mass, and volume will boil at different temperatures. - 10In chemistry, the elements are a. Pure chemical substances containing only one type of atom b. Pure chemical substances containing two or more different types of atoms c. Substances which can be burnt in the presence of air d. Substances which do not react with other substancesAn element is PURE and contains ONE type of atom.
Example: The element gold is pure because it only contains gold atoms. - 11Which of the following do water (H2O), rust (Fe2O3), and salt (NaCl) have in common? a. Water, rust and salt are atoms. b. Water, rust and salt are mixtures. c. Water, rust and salt are elements. d. Water, rust and salt are compounds.They are all compounds.
A compound is formed when two or more elements bond together. - 12The table below shows the number of each kind of atom that makes up one molecule of the compounds sucrose and ethanol. Which of the following is the same for both compounds? a. the mass of each molecule b. the length of each molecule c. the types of atoms in each molecule d. the number of atoms in each moleculeThe types of atoms in each molecule
The table shows that both sucrose and ethanol contains carbon, oxygen, and hydrogen atoms.
- 13The figure shows a toaster that toasts bread. Which energy conversion takes place when a toaster is switched on? a. chemical to sound a. chemical to sound c. chemical to thermal d. electrical to thermalelectrical to thermal
Plugging in the toaster is electricity being used to make heat (thermal)
- 14Which statement best describes the energy changes that occur while a child is riding on a sled down a steep, snow-covered hill? a. Kinetic energy decreases and potential energy increases. b. Kinetic energy increases and potential energy decreases. c. Both potential energy and kinetic energy decrease. d. Both potential energy and kinetic energy increase.Kinetic increases and potential decreases
Potential energy is highest at the top of the hill and decreases as you go down the hill
Kinetic energy is lowest at the top of the hill and increases and you go down the hill. It is highest at the bottom of the hill. - 15At what point in its fall does the kinetic energy of a falling object equal its potential energy? a. at the start of the fall b. halfway between the start and the end c. at the end of the fall d. at all points during the fallhalfway between the start and the end
Potential energy decreases during a fall and kinetic energy increases during a fall. This means they would be equal 1/2 way through the fall. - 16The diagram shows a boulder rolling down a hill into a valley and then up the opposite hill. At which position does the boulder have the greatest kinetic energy?B
Kinetic energy is greatest at the bottom of a fall.
- 17David aims and shoots a basketball into the net. The dotted arrows in the diagram above show the path of the basketball. At which point is the kinetic energy the highest?C
Kinetic energy is greatest right before touching the ground.
- 18David aims and shoots a basketball into the net. The dotted arrows in the diagram above show the path of the basketball. At which point is the potential energy the highest?B
Potential energy is greatest at the highest point. - 19Which of the following models correctly represents the compound phosphorus trichloride (PCl3)?A
In the compound PCl3, I have one P atom (dark grey atoms) and 3 Cl atoms (Light grey atoms).
- 20The liquid in a thermometer rises when the temperature increases. This is because the particles in the liquid a. move faster and spread apart b. lose heat energy and condense c. move slower and spread apart d. lose heat energy and evaporateAs the temperature increases, particles SPEED UP and move FURTHER APART
- 21The diagram shows two magnets. If the magnets are brought closer together, they will a. attract each other with a stronger force b. stay in the same position c. repel each other with a stronger forceIn magnets, opposites attract. The picture shows the both magnets have the North Pole facing each other. Because they are both the same they will repel each other.
- 22Which of the following sets of tools would be most useful in an experiment measuring the rate of transfer of thermal energy in four different liquids? a. Triple-beam balance, beakers, metric ruler b. Hot plate stove, beakers, thermometers c. Microscope, funnel, metric ruler d. pH meter, test tubes, forcepsThermal means HEAT...this means you would use a hot plate, beaker, and thermometer
- 23Which graph correctly shows the effect of heat energy on the motion of molecules of matter?With heat...as temperature increases, motion increases...the only graph that shows motion increasing as temperature increases is C.
- 24Given the diagrams X, Y, and Z below, Which diagram or diagrams represent compound? a. X only b. X and Y c. Y only d. X and ZX only
A compound must be composed of at least TWO DIFFERENT elements.
- 25Use Newton’s second Law of Motion to calculate how much force would be necessary to move a 100 kg object at a speed of 2 m/s2. a. 50 N b. 200 N c. 102 N d. not enough informationF = m * A
F = 100kg * 2 m/s2
So 200 N is the correct answer - 26The graph below shows distance and time for one of Anna’s swimming races. What is Anna’s average speed? a. 2 m/s b. 6 m/s c. 8 m/s d. 72 m/sAccording to the graph, every second she is moving 2 m...so her speed is 2m/s
- 27During which span of time was the beetle not moving? a. 0-4 minutes b. 4-6 minutes c. 6-14 minutes d. 14-16 minutesThe beetle was not moving from minute 6 to minute 14.
- 28How many centimeters were traveled in the first 6 minutes? a. 6 cm b. 8 cm c. 4 cm d. 16 cmAccording to the graph, the beetle moved 8 cm in the first 6 minutes
- 29For an object to remain at rest, which of the following must be true? a. The forces on it are balanced. b. There is no friction. c. Gravity does not act on it. d. The object has no mass.For an object to stay at rest, the forces on it must be balanced.
- 30Read the following statements. Which one is NOT a great illustration of Newton’s 3rd Law of Motion? a. Firefighters hold hoses firmly because as the water shoots out, the hose is pushed back. b. A car speeding on the highway slows down when they see a police car. c. A cannon jumps back as it is fired by a soldier. d. When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your bodyNewton's 3rd Law states that for every action (force) there is an EQUAL and OPPOSTITE reaction.
The statement that does not apply to Newton's 3rd Law is...
A car speeding on the highway slows down when they see a police car.
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- Flashcards on 8th Grade Physical Science Final Review, created by Dana Cowan on 24/05/2023.
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