Science Unit 2 Review

In an experiment, two students timed how long salt took to dissolve in water under the four conditions shown below.

Condition 1: No stirring and no heat

Condition 2: Stirring and no heat

Condition 3: No stirring with heat

Condition 4: Stirring and heat

The students carefully recorded the time it took for the salt to dissolve under each set of conditions. However, they forgot to label which condition went with each set of times. The table shows the data from the three trials.

Which set of data most likely shows the beaker in Condition 4, with stirring and heat?

• Beaker 1

• Beaker 2

• Beaker 3

• Beaker 4

Family members on a camping trip decide to make hot cocoa after dinner. They add instant cocoa mix to hot water. What can they do to make the cocoa mix dissolve faster?

• stir the hot cocoa

• have the amount of water

• double the amount of cocoa mix added

• add the cocoa mix after the water cools

Maria likes iced tea and her mom likes hot tea. Maria poured the same amount of hot tea into a glass with ice as her mom poured into a cup. Then they stirred the same amount of sugar into each of their teas.

After they both finished their tea, Maria noticed there was still sugar at the bottom of her glass, while her mom’s cup did not have any sugar left. What was the most likely reason that sugar was left at the bottom of the iced tea but NOT at the bottom of the hot tea?

• Maria's drink was stirred more

• Maria's glass had less tea in it than her mom's cup had.

• Maria's drink was in a glass and her mom's was in a cup.

• Maria's tea was at a lower temperature than her mom's tea.

Ken needs to design an experiment that shows how the surface area of sugar affects the rate at which the sugar will dissolve in water. Which of the following statements describes the best way to show the relationship between particle size and rate of dissolving?

• Time how fast loose sugar dissolves in water at room temperature and how fast loose sugar dissolves in hot water.

• Time how fast a cube of sugar dissolves in water at room temperature and how fast loose sugar dissolves in hot water.

• Time how fast a cube of sugar dissolves in water at room temperature and how fast a cube of sugar dissolves in hot water.

• Time how fast a cube of sugar dissolves in water at room temperature and how fast loose sugar dissolves in water at room temperature.

A student is making a list of items that will not dissolve in water. Which of the following substances can be added to this list?

• salt

• soap

• sugar

• oil

Both brick and glass are often used in building houses. Which of the following properties is most different when comparing a brick paver and a sliding glass door?

• shape

• hardness

• temperature

• state of matter

A rubber band is made of rubber and is often used to hold things together. Which property of a rubber band will stay the same when the rubber band is stretched?

• length

• mass

• shape

• width

At 10 degrees Celsius (°C), a continuous body of matter fills the bottom of a container. This matter is yellow in color and has a definite volume. How would this matter be classified?

• gas

• liquid

• plasma

• solid

Diego carefully places ten marbles into a graduated cylinder filled with water, making sure no water splashes out. He then measures how high the water level rises and divides this value by ten. He then repeats this process using ten pennies. What property of the marbles and the pennies can Diego now directly compare?

• mass

• shape

• temperature

• volume

Kaitlyn grew bean plants outside in different soils for her school science fair. She completed her experiment three times. For each trial, Kaitlyn recorded the height of each plant daily and also wrote observations in her experiment log. Kaitlyn noticed that the second time she completed the experiment, her data was very different from the data in the other two experiments. Which of the following observations in Kaitlyn’s experiment log best explains the difference?

• She watered her plants the same amount each day

• She followed her procedure very carefully each time.

• It rained for three days during the second experiment.

• The plants were all grown on the patio behind her house.