ACT science practice test 78

Directions: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.


The melting point of a substance is the temperature at which the solid phase transitions to the liquid phase. When a substance melts, the attractive forces holding the molecules together are reduced sufficiently to allow the molecules to flow. The stronger the intermolecular forces in solid form, the higher the melting point will be.

The boiling point of a substance is the temperature at which the vapor pressure in the liquid phase equals the atmospheric temperature of its surroundings. When a substance boils, the substance transitions from a liquid phase to a gaseous phase and the intermolecular forces are completely severed. The stronger the attractive forces between the molecules in the liquid phase, the higher the boiling point will be.

Table 1 and Figure 1 show details of some of the elements from the third row of the periodic table.

Table 1

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Figure 1

1. The melting point of silicon is closest to which temperature?

A. 700 K
B. 1200 K
C. 1700 K
D. 2200 K

2. Based on Table 1 and Figure 1, what can be concluded about the relationship between the number of protons in the nucleus and the attractive forces between molecules?

F. As the number of protons increase, the intermolecular forces increase.
G. As the number of protons increase, the intermolecular forces decrease.
H. As the number of protons increase, the intermolecular forces are unchanged.
J. There is no relationship between the number of protons and the intermolecular forces.

3. Based on Figure 1, what is the relationship between melting point (MP) and boiling point (BP)?

A. There is a direct relationship between melting point and boiling point and the constant of variation is roughly 2. The equation would be MP ≈ 2 ·(BP).
B. There is a direct relationship between melting point and boiling point and the constant of variation is roughly img. The equation would be MPimg · (BP).
C. There is an inverse relationship between melting point and boiling point and the constant of variation is roughly 1.5 · 106. The equation would be (BP)≈ 1.5 · 106.
D. There is a direct relationship between melting point and boiling point but no constant of variation exists. When melting point increases, boiling point also increases but every element has a different numerical relationship.

4. Which element transitions from a liquid phase to a gaseous phase at 500 K?

F. P
G. Al
H. Mg
J. Na

5. Do Figure 1 and Table 1 support the conclusion that nonmetals have melting points and boiling points that are closer in temperature than the metals?

A. Yes. Phosphorus, sulfur, and chlorine all have melting points and boiling points that are less than 500 K apart. Sodium, magnesium, and aluminum have boiling points that are 500 K or more apart.
B. Yes. Phosphorus, sulfur, and chlorine all have melting points and boiling points that are less than 1000 K apart. Sodium, magnesium, and aluminum have boiling points that are more than 1000 K apart.
C. No. Silicon’s melting point is 1000 K less than its boiling point. Magnesium’s melting point is 500 K less than its boiling point.
D. No. There is no general relationship between melting points and boiling points and an element’s classification as a metal or a nonmetal.

From 1971 to 2006, there was a dramatic reduction in the number of feral honeybees in the United States, and a significant, though somewhat gradual, decline in the number of colonies maintained by beekeepers. In early 2007 the rate of attrition reached new proportions, and the term Colony Collapse Disorder (CCD) was coined to describe this sudden decline. CCD is said to have occurred when a bee colony abruptly disappears, with little or no build-up of dead bees in or around the colonies. The cause or causes of the syndrome are not yet well understood. Proposed causes include environmental change-related stress, malnutrition, disease, and pests.

Study 1

In an attempt to quantify the degree and extent of losses experienced in the United States, scientists tracked beekeeping operations with various numbers of colonies between September 2006 and March 2007. For the sake of this study, a colony has encountered CCD when it loses at least 90% of its population in a period of 30 days. This loss must be accompanied by little or no trace of dead bees in or around the hive. Figure 1 displays the total losses experienced by all beekeeping operations.

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Figure 1

Study 2

Scientists studying CCD surveyed beekeepers whose hives have been affected by the disorder. The beekeepers were asked what they believe caused the CCD in their colonies. Table 1 displays the five most commonly suspected causes of CCD losses and the average percentage of loss experienced by operations of varying sizes due to each suspected cause. The scientists then surveyed beekeepers whose hives had collapsed for reasons unrelated to CCD, asking them the same question. Figure 2 compares the results from the scientists’ two surveys, displaying the total loss experienced due to suspected causes of CCD and non-CCD losses, averaged for operations of all sizes.

Table 1

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Figure 2

6. Beekeepers from operations of which size experienced the lowest total losses by percentage?

F. 1 to 50
G. 51 to 500
H. 500+
J. It cannot be determined from the data provided.

7. Based on the data in Figure 2, it can be determined that the least common suspected cause of CCD losses was:

A. starvation.
B. weak in fall.
C. weather.
D. queen death.

8. According to Study 2, for operations with between 1 and 50 colonies, what was the most common suspected cause of CCD losses?

F. Starvation
G. Weak in fall
H. Weather
J. Queen death

9. Prior to conducting the research, four scientists each proposed one of the following hypotheses. Which hypothesis is best supported by the results?

A. Environmental changes, including shifts in weather patterns, are the predominant causes of CCD-related loss.
B. An increase in pesticide-resistant pests is the main contributing factor to CCD loss at small beekeeping operations.
C. The larger a beekeeping operation, the higher the overall CCD loss will be.
D. A shortage of food sources, especially at smaller beekeeping operations, is leading to an increase in CCD loss.

10. Figure 2 indicates that, compared with the total loss for non-CCD, the total loss for CCD was higher for which of the following causes?

F. Starvation, weather, and pests
G. Weak in fall and queen death
H. Weak in fall and weather
J. Starvation and pests

11. A scientist theorized that the number of CCD losses would be higher than non-CCD losses for beekeeping operations of all sizes. Does the data support this theory?

A. Yes. For all causes the total loss was higher for CCD than for non-CCD.
B. Yes. Starvation was the most common cause of loss regardless of operation size.
C. No. For many of the causes there were more non-CCD losses than CCD losses.
D. No. Operations with 51 to 500 colonies experienced the greatest total loss.

12. Both Study 1 and Study 2 scientists gathered data directly from which of the following sources?

F. Feral honeybee colonies only
G. Feral honeybee colonies and non-CCD honeybee colonies
H. Non-CCD honeybee colonies only
J. CCD honeybee colonies and non-CCD honeybee colonies