ACT Science Practice Test 119

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.


Carbon monoxide (CO) is a colorless, odorless gas produced by burning material that contains carbon, such as coal or natural gas. Carbon monoxide is the leading cause of accidental poisoning deaths in America. The Centers for Disease Control estimates that carbon monoxide poisoning claims nearly 500 lives and causes more than 15,000 visits to hospital emergency departments annually. Common household appliances produce carbon monoxide. When not properly ventilated, carbon monoxide emitted by these appliances can build up. The only way to detect carbon monoxide is through testing, using a specialized sensing device.

Gas stoves have been known to emit high levels of carbon monoxide. Average carbon monoxide levels in homes without gas stoves vary from 0.5 to 5.0 parts per million (ppm). Levels near properly adjusted gas stoves are often 5.0 to 15.0 ppm and those near poorly adjusted stoves may be 30.0 ppm or higher. CO levels between 0.5 and 15.0 ppm are considered safe.

Table 1 shows the carbon monoxide levels in ppm for each of five homes, with and without gas stoves.

1. According to the passage, which of the following homes listed in Table 1 most likely has a poorly adjusted gas stove?

A. 5
B. 4
C. 3
D. 1

2. A sensing device was installed in Home 2 to test CO levels. Which of the following is most likely true about the results of the test?

F. The results indicated below average CO emissions.
G. The results indicated above average CO emissions.
H. The results indicated average CO emissions.
J. The results indicated no CO emissions.

3. According to the passage, which of the following carbon monoxide levels would be considered most harmful?

A. 40.25 ppm
B. 12.00 ppm
C. 6.50 ppm
D. 0.30 ppm

4. According to the passage, if Home 4 has a gas stove, should it be removed?

F. Yes, because it is emitting a high level of carbon monoxide.
G. Yes, because it is not properly adjusted.
H. No, because carbon monoxide levels in the house are within a safe range.
J. No, because there is no indication of any carbon monoxide emissions.

5. Suppose a 6th home was tested for carbon monoxide and the results showed a carbon monoxide level of 10.0 ppm. According to the passage, which of the following conclusions can be reached?

A. The residents of Home 6 are highly susceptible to CO poisoning.
B. Home 6 has a poorly adjusted gas stove that should be repaired or removed.
C. The CO levels in Home 6 will not pose any danger to the residents.
D. The CO sensing device is defective and should be replaced.