P/C Changes
Which is an example of a physical change?
A. Burning a piece of paper
B. Melting an ice cube
C. Rusting a bicycle
B. Melting an ice cube
Which statement best describes a chemical change?
A. The substance changes only in size or shape.
B. The substance changes from a solid to a liquid.
C. One or more new substances are formed.
C. One or more new substances are formed.
What is an aqueous solution?
A. A solution in which water is the solvent
B. A mixture containing only solids
C. A substance that cannot dissolve
A. A solution in which water is the solvent
A student dissolves 20 grams of sugar in 100 mL of water. Another student dissolves 5 grams of sugar in 100 mL of water. Which solution is more concentrated?
A. The 5-gram solution
B. Both have the same concentration.
C. The 20-gram solution
C. The 20-gram solution
Which factor can increase the rate at which a solid dissolves in water?
A. Lowering the temperature
B. Increasing the temperature
C. Removing the solvent
B. Increasing the temperature
Which change produces a new substance?
A. Chemical change
B. Physical change
C. Change of state
A. Chemical change
A student mixes two substances and notices that the mixture becomes warmer and produces bubbles. What is the most likely explanation?
A. A chemical change occurred.
B. Only the shape changed.
C. The substances experienced a physical change.
A. A chemical change occurred.
What is the substance that does the dissolving in a solution called?
A. Solute
B. Solvent
C. Concentration
B. Solvent
Which substance would be the solute in lemonade?
A. Water
B. Sugar
C. The glass
B. Sugar
Why does stirring usually make a solid dissolve faster?
A. It increases the amount of solute.
B. It changes the solute into a gas.
C. It brings fresh solvent into contact with the solute.
C. It brings fresh solvent into contact with the solute.
A student cuts a piece of paper into smaller pieces. What type of change occurred?
A. Chemical change
B. Both types of change
C. Physical change
C. Physical change
Which is an example of a change of state?
A. Burning gasoline
B. Melting chocolate
C. Rusting metal
B. Melting chocolate
In salt water, which substance is the solute?
A. Water
B. Salt
C. The container
B. Salt
What does it mean when a substance is soluble?
A. It can dissolve in a particular solvent.
B. It cannot mix with another substance.
C. It always forms a gas.
A. It can dissolve in a particular solvent.
Which would dissolve a sugar cube the fastest?
A. Crushed sugar in warm water with stirring
B. A whole sugar cube in cold water without stirring
C. A whole sugar cube in cold water with stirring
A. Crushed sugar in warm water with stirring
Which is evidence that a chemical change may have occurred?
A. A substance changes shape
B. A gas is produced when two substances are mixed
C. A solid is broken into smaller pieces
B. A gas is produced when two substances are mixed
Why is cooking an egg considered a chemical change?
A. The egg changes color only.
B. The egg becomes a different shape.
C. New substances are formed during cooking.
C. New substances are formed during cooking.
In a sugar-water solution, what is the solvent?
A. Sugar
B. The solution
C. Water
C. Water
A student adds salt to water and stirs until the salt is no longer visible. What has most likely happened?
A. The salt evaporated.
B. The salt dissolved.
C. The water disappeared.
B. The salt dissolved.
How does surface area affect the rate of dissolution?
A. Decreasing surface area always makes dissolving faster.
B. Increasing surface area generally makes dissolving faster.
C. Surface area has no effect on dissolving.
B. Increasing surface area generally makes dissolving faster.
What happens to the identity of a substance during a physical change?
A. It stays the same
B. It changes into a new substance
C. It disappears
A. It stays the same
Which change can usually be reversed without forming a new substance?
A. Physical change
B. Chemical change
C. Combustion
A. Physical change
What happens when a solute dissolves in a solvent?
A. The solute becomes evenly distributed throughout the solvent.
B. The solute always disappears completely.
C. The solvent turns into a solid.
A. The solute becomes evenly distributed throughout the solvent.
Which action would increase the concentration of a solution?
A. Adding more solvent
B. Adding ice cubes
C. Adding more solute
C. Adding more solute
A student places equal amounts of sugar into two cups. Cup A contains hot water, and Cup B contains cold water. Which sugar will dissolve faster?
A. The sugar in Cup A
B. The sugar in Cup B
C. They will dissolve at exactly the same rate.
A. The sugar in Cup A
Which example represents a chemical change?
A. Water freezing
B. Crushing a can
C. Wood burning
C. Wood burning
A student tears a sheet of paper into four pieces. Which statement is correct?
A. A new substance formed.
B. The paper's size and shape changed, but it is still paper.
C. The paper underwent a chemical reaction.
B. The paper's size and shape changed, but it is still paper.
Which of the following is an example of an aqueous solution?
A. Sand mixed with gravel
B. Salt dissolved in water
C. Rocks mixed together
B. Salt dissolved in water
Which statement correctly identifies the parts of a saltwater solution?
A. Salt is the solvent and water is the solute.
B. Water is the solvent and salt is the solute.
C. Salt and water are both solvents.
B. Water is the solvent and salt is the solute.
Which action would most likely slow down the rate of dissolution?
A. Stirring the solution
B. Crushing the solid into smaller pieces
C. Using colder water
C. Using colder water
A puddle of water disappears on a warm day. What type of change is this?
A. Chemical change
B. Physical change
C. Nuclear change
B. Physical change
Which observation provides the strongest evidence of a chemical change?
A. A solid is crushed into powder.
B. Water changes from liquid to solid.
C. A solid forms when two liquids are mixed.
C. A solid forms when two liquids are mixed.
What does concentration describe?
A. The color of a solution
B. The temperature of a solution
C. The amount of solute compared to the amount of solution
C. The amount of solute compared to the amount of solution
A solution contains a small amount of solute compared with the amount of solvent. How would you describe the solution?
A. Dilute
B. Concentrated
C. Saturated
A. Dilute
Two students are dissolving equal amounts of salt. Student 1 stirs the water, while Student 2 does not. What will most likely happen?
A. The unstirred salt will dissolve faster.
B. The stirred salt will dissolve faster.
C. Both will always dissolve at exactly the same rate.
B. The stirred salt will dissolve faster.
Which of the following is NOT usually evidence of a chemical change?
A. Formation of a new substance
B. Production of a gas
C. Change in size
C. Change in size
Which of these is a chemical change?
A. Silver tarnishing
B. Ice melting
C. Sugar dissolving in water
A. Silver tarnishing
Which solution has the greatest concentration?
A. 10 g of salt in 100 mL of water
B. 5 g of salt in 100 mL of water
C. 2 g of salt in 100 mL of water
A. 10 g of salt in 100 mL of water
Which solution is the most dilute?
A. 15 g of sugar in 100 mL of water
B. 10 g of sugar in 100 mL of water
C. 2 g of sugar in 100 mL of water
C. 2 g of sugar in 100 mL of water
Which situation demonstrates the effect of surface area on dissolution?
A. Comparing powdered sugar with a sugar cube in the same conditions
B. Comparing hot water with cold water
C. Comparing stirred water with unstirred water
A. Comparing powdered sugar with a sugar cube in the same conditions
When an iron nail develops rust, what type of change has occurred?
A. Physical change
B. Chemical change
C. Change of state
B. Chemical change
Which pair contains TWO physical changes?
A. Burning wood and rusting iron
B. Melting ice and cutting paper
C. Cooking an egg and baking a cake
B. Melting ice and cutting paper
A student adds more water to a salt solution. What happens to the concentration?
A. It increases.
B. It decreases.
C. It stays exactly the same.
B. It decreases
A student has a concentrated solution and wants to make it less concentrated. What should the student do?
A. Add more solute.
B. Add more water.
C. Remove some water.
B. Add more water.
A student wants to investigate how temperature affects the rate of dissolution. Which variables should be kept the same?
A. Temperature only
B. The amount of solute and solvent
C. The temperature and amount of solute
B. The amount of solute and solvent
Which situation is an example of a physical change?
A. A glass breaking
B. An egg cooking
C. A candle wick burning
A. A glass breaking
Which pair contains TWO chemical changes?
A. Breaking glass and melting ice
B. Cutting wood and crushing a can
C. Burning wood and rusting metal
C. Burning wood and rusting metal
What is dilution?
A. Adding solvent to decrease the concentration of a solution
B. Adding more solute to increase concentration
C. Removing all of the solvent
A. Adding solvent to decrease the concentration of a solution
Which statement best describes a solution?
A. A mixture in which one substance is evenly distributed throughout another
B. A mixture in which substances always remain separated
C. A substance made only of water
A. A mixture in which one substance is evenly distributed throughout another
Which combination would generally produce the fastest rate of dissolution for a solid solute?
A. Cold water, large pieces, no stirring
B. Warm water, large pieces, no stirring
C. Warm water, small pieces, stirring
C. Warm water, small pieces, stirring