TEAS 7 science practice

TEAS 7 science practice Related

Review TEAS 7 science practice related questions and content

When unpolarized light passes through a polarizing filter, the intensity of the transmitted light is:

  • A. Completely absorbed
  • B. Reduced by half
  • C. Unaffected
  • D. Doubled
Correct Answer: B

Rationale: When unpolarized light passes through a polarizing filter, the filter only allows light waves oscillating in a specific direction to pass through while blocking light waves oscillating in other directions. Since unpolarized light consists of light waves oscillating in all possible directions, when it passes through a polarizing filter, only half of the light waves (those oscillating in the direction allowed by the filter) are transmitted. As a result, the intensity of the transmitted light is reduced by half. Choice A is incorrect because the light is not completely absorbed; choice C is incorrect because the polarizing filter affects the transmitted light; and choice D is incorrect because the intensity does not double, but rather decreases by half due to the selective transmission of light waves in a specific direction by the polarizing filter.

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When ethanol (Câ‚‚Hâ‚…OH) reacts with sodium metal (Na), what is the product?

  • A. Ethene (Câ‚‚Hâ‚„)
  • B. Sodium ethoxide (Câ‚‚Hâ‚…ONa)
  • C. Ethane (Câ‚‚H₆)
  • D. Sodium acetate (CH₃COONa)
Correct Answer: B

Rationale: When ethanol (C₂H₅OH) reacts with sodium metal (Na), the product formed is Sodium ethoxide (C₂H₅ONa). This reaction is a classic example of a metal displacing hydrogen in an alcohol to form an alkoxide. In this specific case, sodium replaces the hydrogen in ethanol, resulting in the formation of sodium ethoxide. Choice A, Ethene (C₂H₄), is incorrect as it is a different compound formed from the dehydration of ethanol, not its reaction with sodium. Choice C, Ethane (C₂H₆), is incorrect as it is a saturated hydrocarbon, not the product of the reaction of ethanol with sodium metal. Choice D, Sodium acetate (CH₃COONa), is incorrect as it involves acetic acid, not ethanol, reacting with sodium to form the salt sodium acetate.

What property of a substance remains constant regardless of changes in its location in the universe?

  • A. Mass
  • B. Weight
  • C. Density
  • D. Volume
Correct Answer: A

Rationale: Mass is the amount of matter in an object and remains constant regardless of its location in the universe. Weight, on the other hand, is the force of gravity acting on an object and can vary depending on the gravitational pull at different locations. Density and volume can change based on the conditions the substance is in, so they are not constant properties. Therefore, the correct answer is mass as it does not change with changes in location.

What happens to the work done on an object when the angle between the force and displacement is 90 degrees?

  • A. Maximum work is done
  • B. No work is done
  • C. Minimum work is done
  • D. Work is infinite
Correct Answer: B

Rationale: When the angle between the force and displacement is 90 degrees, the work done is given by the formula W = F * d * cos(theta), where theta is the angle between the force and displacement vectors. Since cos(90 degrees) = 0, the work done becomes zero. This means that no work is done on the object when the angle between the force and displacement is 90 degrees. Choice A is incorrect because maximum work is done when the force and displacement are in the same direction (theta = 0 degrees). Choice C is incorrect as minimum work is done when the force and displacement are parallel (theta = 0 degrees), not perpendicular. Choice D is incorrect because work cannot be infinite; it depends on the force, displacement, and the cosine of the angle between them.

Which of the following is a characteristic of unsaturated fatty acids?

  • A. They are solid at room temperature.
  • B. They contain only single bonds.
  • C. They have a higher melting point.
  • D. They contain double or triple bonds.
Correct Answer: D

Rationale: The correct answer is D. Unsaturated fatty acids are characterized by the presence of double or triple bonds in their carbon chain. These bonds introduce kinks in the chain, preventing tight packing, and resulting in a lower melting point compared to saturated fatty acids. Choice A is incorrect because unsaturated fatty acids are typically liquid at room temperature due to their kinked structure. Choice B is incorrect because unsaturated fatty acids contain double or triple bonds, not only single bonds. Choice C is incorrect as unsaturated fatty acids have a lower melting point compared to saturated fatty acids.

Which element has the lowest electronegativity value?

  • A. Oxygen
  • B. Fluorine
  • C. Helium
  • D. Chlorine
Correct Answer: C

Rationale: The correct answer is Helium (C). Electronegativity is the tendency of an atom to attract electrons towards itself in a bond. Helium, as a noble gas, has a very low electronegativity because its outer electron shell is already full and stable, resulting in minimal attraction for additional electrons. Oxygen (A), Fluorine (B), and Chlorine (D) are all non-noble gas elements that have higher electronegativity values compared to Helium due to their electron configurations and tendencies to attract electrons.

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