8th Grade Physical Science Chapter 2 Review
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- 1.The ability of an object to transfer heat is known as thermal conductivity. Which of the following types of elements has the most efficient thermal conductivity?
- A.
Semimetals
- B.
Metals
- C.
Nonmetals
- D.
Gases
- 2.When investigating a chemical reaction, one would expect the products to have:
- A.
The same properties as the reactants have separately
- B.
A mixture of the properties of the reactants
- C.
Different properties than the reactants separately
- D.
The same properties as only one of the reactants
- 3.A student has two solid samples of the same substance. Which property do the substances MOST likely have in common
- A.
Density
- B.
Mass
- C.
Shape
- D.
Volume
- 4.Coppers and other metals are often used in making pots and pans to cook in. What property would BEST explain why?
- A.
Conductivity because it is a chemical property
- B.
Conductivity because it is a physical property
- C.
Insulation because it is a chemical property
- D.
Insulation because it is a physical property
- 5.A student divides several objects into two groups based on their ability to float in water. Which property is the student using to classify the objects?
- A.
Mass
- B.
Density
- C.
Weight
- D.
Phase
- 6.Which of the following is NOT a physical property that a substance can be classified by?
- A.
Hardness
- B.
Thermal conductivity
- C.
Reactivity
- D.
Density
- 7.Water has a density of 1 g/mL. Which object will float in water?
- A.
An object that has a density of 1.2 g/mL
- B.
An object that has a density of 10 g/mL
- C.
An object that has a density of 0.1 m/mL
- D.
An object that has a density of 100 m/mL
- 8.Before the onset of a snowstorm, people spread salt on roads and sidewalks. Which property of salt explains this behavior?
- A.
Salt decreases the combustion rate of water
- B.
Salt decreases the freezing point of water
- C.
Salt increases the freezing rate of water
- D.
Salt increases the reactivity of water
- 9.Which of the following will NOT occur when water undergoes a physical change?
- A.
The motion of the molecules increases
- B.
The molecules form new chemical bonds
- C.
The molecules become less closely packed
- D.
The kinetic energy of molecules increases
- 10.Which of the substances is MOST soluble in water?
- A.
Wood
- B.
Salt
- C.
Sand
- D.
Iron
- 11.Jonas was making bread. The chart shows the steps in the recipe he was using. Steps in making bread
- combine the two cups of flour with sugar, and yeast
- heat milk, water, and butter until warm
- beat two minutes.
- add one egg and one cup of flour
- knead (press) the dough until it's smooth
- cover and place in a warm place so the dough can rise
- place in a pan and bake at 325 degrees F for 20 minutes
- A.
Combining the flour with the sugar
- B.
Kneading the dough until smooth
- C.
Adding the egg and a cup of flour
- D.
Baking the dough in the oven
- 12.Which of the following is an example of a chemical change
- A.
A piece of glass breaking
- B.
An apple turning brown
- C.
Folding a piece of paper
- D.
Cutting an orange in half
- 13.ORIGINAL MATERIALEVENTCHANGEpiece of ironleft outdoors in the rainrust formsstack of fire woodused in fireplacebecomes smoke and ashescopper pennyplaced in vinegargas bubbles formThe chart shows how materials can change chemically.Why are these changes classified as chemical changes?
- A.
New substances are formed
- B.
Materials take different shapes
- C.
Temperature affects the object
- D.
Some energy is absorbed
- 14.Which part of digestion is mainly a chemical change
- A.
Teeth break food into smaller pieces
- B.
Throat muscles push food toward the stomach
- C.
Stomach acids dissolve food into nutrients
- D.
Intestinal cells transport nutrients into the blood
- 15.Experimentdescription1Student blows through a straw into his milk carton; bubbles are produced 2Student blows through a straw into a beaker of limewater; bubbles are produced and the liquid becomes cloudy; small, white solid particles appearThe table above describes two experiments What can the student conclude about the experiments?
- A.
Experiment 1 shows a physical change because the temperature changed
- B.
Experiment 1 shows a chemical change because bubbles were produced
- C.
Experiment 2 shows a physical change because its color changed
- D.
Experiment 2 shows a chemical change because a new substance was produced
- 16.Which is a physical change
- A.
A piece of wood burning
- B.
A copper roof changing colors
- C.
Rust forming on an iron fence
- D.
A sheet of paper shredding
- 17.Cutting a piece of paper, crushing salt into smaller pieces, and a pencil being sharpened are all examples of what
- A.
Chemical changes
- B.
Chemical properties
- C.
Physical changes
- D.
Physical properties
- 18.Physical changes are
- A.
Always reversible
- B.
Always irreversible
- C.
Reversible with some materials
- D.
Irreversible with pure substances
- 19.Which is an indication that a chemical change is taking place
- A.
Iron changes color when heated
- B.
Gas bubbles form in boiling water
- C.
Solid wax forms when melted wax falls in ice water
- D.
A gas forms when vinegar and baking soda are mixed
- 20.A scientist placed a sample of lithium into a container of water. The scientist observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Which conclusion is BEST supported by this observation
- A.
A chemical change took place
- B.
The lithium was dissolved by the water
- C.
Dissolved gases were released
- D.
Water was vaporized
- 21.The process of digestion breaks down proteins into smaller molecules that are used to rebuild other proteins. During digestion, proteins undergo
- A.
Cell division
- B.
Nuclear reactions
- C.
Natural selection
- D.
Chemical changes
- 22.Which of the following is a chemical property of a substance
- A.
Mass of 372 g
- B.
Reacts with HCI
- C.
Density of 37 g/cm (squared)
- D.
White powder with silver specks
- 23.Which of the following processes rearranges atoms during a reaction
- A.
Burning
- B.
Cooling
- C.
Crushing
- D.
Evaporating
- 24.Chemical compounds undergo both physical and chemical changes. Which of the following is an example of a physical change
- A.
Salt (NaCI) being dissolved into water
- B.
Combining oxygen gas and hydrogen gas to form to form liquid water
- C.
Reordering atoms in a molecule
- D.
Heat being released when combining two substances
- 25.During photosynthesis, carbon dioxide and water combine according to the general equation: Carbon dioxide+water : energy------------> sugar+oxygenWhy is photosynthesis a chemical reaction
- A.
Because new substances are formed
- B.
Because an input on energy is required
- C.
Because the reactants are compounds
- D.
Because the products include an element
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