TEAS 7 science practice questions

TEAS 7 science practice questions Related

Review TEAS 7 science practice questions related questions and content

When calcium chloride (CaCl2) dissolves in water, it separates into its ions (Ca2+ and Cl-). This is an example of:

  • A. Chemical change
  • B. Physical change
  • C. Precipitation
  • D. Neutralization
Correct Answer: B

Rationale: When calcium chloride dissolves in water, it separates into its ions without forming a new substance, which is characteristic of a physical change. A physical change involves alterations in the substance's physical properties without changing its chemical composition. In this scenario, the chemical formula of calcium chloride remains unchanged, and only its physical state changes by creating ions in the solution. Therefore, the dissolution of calcium chloride in water is an example of a physical change. Choice A, 'Chemical change,' is incorrect because no new substances are formed during the dissolution process. Choice C, 'Precipitation,' is incorrect as precipitation involves the formation of an insoluble solid when two solutions react. Choice D, 'Neutralization,' is incorrect as it refers to a reaction between an acid and a base to form salt and water, which is not the case in the given scenario.

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Which property describes a substance's resistance to flow?

  • A. Density
  • B. Viscosity
  • C. Conductivity
  • D. Reactivity
Correct Answer: B

Rationale: Viscosity is the property that describes a substance's resistance to flow. A substance with high viscosity flows slowly, while a substance with low viscosity flows quickly. Density (A) is the measure of mass per unit volume; conductivity (C) is the ability of a material to conduct electricity or heat, and reactivity (D) refers to how readily a substance undergoes chemical reactions. Therefore, the correct answer is B, viscosity, as it directly relates to a substance's resistance to flow.

How many moles of water are produced when 0.5 moles of methane (CH4) react with excess oxygen?

  • A. 0.5 moles
  • B. 1 mole
  • C. 2 moles
  • D. 3 moles
Correct Answer: B

Rationale: The balanced chemical equation for the combustion of methane is: CH4 + 2O2 -> CO2 + 2H2O. This equation shows that 1 mole of methane produces 2 moles of water. Therefore, when 0.5 moles of methane react, they will produce 1 mole of water. The ratio of water to methane is 2:1, meaning that for every mole of methane that reacts, it produces 2 moles of water. Since only 0.5 moles of methane are reacting, the amount of water produced will be half of what would be produced if 1 mole of methane reacted, resulting in 1 mole of water being produced. Choice A is incorrect because it does not consider the stoichiometry of the reaction. Choices C and D are incorrect as they do not align with the balanced chemical equation and the stoichiometric ratios involved in the reaction.

Which property of matter measures the amount of space occupied by an object?

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

Rationale: Volume is the property of matter that measures the amount of space occupied by an object. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and density is the mass of an object per unit volume. Volume specifically quantifies the space occupied by an object, making it the correct answer in this context.

Which of the following factors would NOT affect the solubility of a solid solute in a liquid solvent?

  • A. Temperature
  • B. Pressure
  • C. Particle size
  • D. Nature of the solute and solvent
Correct Answer: B

Rationale: Pressure does not typically affect the solubility of a solid solute in a liquid solvent. Solubility is primarily influenced by factors such as temperature, particle size, and the nature of the solute and solvent. Increasing pressure generally has a minimal effect on the solubility of solids in liquids. The impact of pressure on solubility is more significant for gases in liquids rather than solids in liquids. Therefore, option B is the correct answer. Options A, C, and D directly impact the solubility of a solid solute in a liquid solvent. Temperature affects the solubility as it changes the kinetic energy of particles, particle size can impact the surface area available for interaction between solute and solvent, and the nature of the solute and solvent influences their intermolecular interactions and compatibility.

What term describes the maximum displacement of particles from their rest position in a wave?

  • A. Frequency
  • B. Wavelength
  • C. Amplitude
  • D. Velocity
Correct Answer: C

Rationale: The term that describes the maximum displacement of particles from their rest position in a wave is called the amplitude. Amplitude is a measure of the strength or intensity of a wave and is represented by the height of the wave from the rest position to the crest (or trough) of the wave. Frequency (A) refers to the number of complete wavelengths that pass a point in a given time. Wavelength (B) is the distance between two consecutive crests (or troughs) of a wave. Velocity (D) is the speed of the wave, not the maximum displacement of particles from their rest position.

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