Praxis 5005 Practice Test
Question 1 of 5.
Which of the following is a pure substance?
A. Granite rock
B. Toothpaste
C. Sodium chloride crystals
D. Sugar water
Explanation: To identify the pure substance among the options, it is important to recall that a pure substance has a fixed chemical composition and uniform properties, while mixtures consist of two or more components combined physically. Granite rock is not pure since it is composed of different minerals such as quartz, feldspar, and mica, making it a heterogeneous mixture. Toothpaste is also a mixture because it contains many ingredients like abrasives, fluoride, water, and flavoring agents. Sugar water is a homogeneous solution in which sugar is dissolved in water, but it is still a mixture because its components can be separated physically. In contrast, sodium chloride crystals (NaCl) are a chemical compound with a definite formula and consistent composition throughout. This uniformity classifies it as a pure substance. Therefore, the correct choice is sodium chloride crystals since it is the only pure substance in the list.
Question 2 of 5.
The rotation of Earth around its axis is responsible for which of the following?
A. The force of gravity
B. The day and night cycle
C. The temperature differences between seasons
D. The movement of continents relative to one another
Explanation: Rotation day night. Gravity mass. Seasons tilt orbit. Continents drift. 24 hour cycle.
Question 3 of 5.
Which TIIREE of the following agricultural practices are most likely to have a negative impact on the environment?
A. Increasing the amount of fertilizer applied to a field to maximize crop yields
B. Providing a field with excessive amounts of water to maintain ground saturation
C. Applying nonselective herbicides to a field at the end of the growing season to eliminate weeds
D. Planting crops in a field with minimal disturbance of the surface soil to reduce soil erosion
Explanation: Fertilizer excess runoff pollution. Water excess waste salinization. Herbicides nonselective kill beneficial. No till positive. Negative practices harm. D positive conservation.
Question 4 of 5.
Which TWO of the following are powered most directly by the Sun's energy?
A. Surface currents in the ocean
B. Volcanic eruptions
C. Tectonic plate movements
D. Convection in the atmosphere
Explanation: Sun heats water winds currents convection. Volcanoes geothermal. Plates internal heat. Solar drive weather ocean.
Question 5 of 5.
Natural gas-fired power plants are considered greenhouse gas emitters because the burning of natural gas produces which of the following?
A. Hydrogen
B. Radon
C. Carbon dioxide
D. Helium
Explanation: Combustion CO2. Hydrogen fuel. Radon radioactive. Helium inert. Methane burn CO2.