Nokea
What can be predicted using the periodic table?
- A. The properties of each of the elements
- B. The charge of polyatomic ions
- C. The number of isotopes in each element
- D. The potential for discovery of new elements
Correct Answer: A
Rationale: The periodic table serves as a fundamental tool in chemistry, organizing elements based on their atomic number, electron configuration, and recurring chemical properties. Through the arrangement of elements, one can predict various properties of each element. Periodic trends such as atomic radius, electronegativity, and ionization energy allow for the anticipation of element characteristics like reactivity, boiling point, and other physical and chemical properties. Hence, the correct answer is A: The properties of each of the elements can be successfully predicted using the periodic table.
You may also like to solve these questions
What is 119°K in degrees Celsius?
- A. 32°C
- B. -154°C
- C. 154°C
- D. -32°C
Correct Answer: B
Rationale: The correct answer is 'B: -154°C.' To convert Kelvin to Celsius, you subtract 273.15 from the temperature in Kelvin. For 119°K: 119 - 273.15 = -154.15. Thus, 119°K is equal to approximately -154°C.
Which of the following statements about dissociation is false?
- A. It is reversible.
- B. Ions are not present.
- C. It involves molecules separating.
- D. None of the above.
Correct Answer: B
Rationale: The correct answer is B - 'Ions are not present.' Dissociation involves the separation of molecules into ions. It is a reversible process where molecules break apart into ions. Choice A is true as dissociation is reversible, and Choice C is accurate as it correctly describes the process of dissociation. Therefore, the false statement is that ions are not present during dissociation.
What is the name of the device that separates gaseous ions by their mass-to-charge ratio?
- A. mass spectrometer
- B. interferometer
- C. magnetometer
- D. capacitance meter
Correct Answer: A
Rationale: The correct answer is a mass spectrometer. A mass spectrometer is a device specifically designed to separate gaseous ions based on their mass-to-charge ratio. The separation occurs as ions pass through the mass spectrometer, allowing for the identification and quantification of compounds present in a sample. This analytical instrument is widely used in chemistry and other scientific fields due to its ability to provide detailed information about the composition of substances.
What is the pH of a solution with a pH of 7?
- A. Acidic
- B. Basic
- C. Neutral
- D. Positive
Correct Answer: C
Rationale: The correct answer is C: Neutral. A pH of 7 is considered neutral on the pH scale, which ranges from 0 to 14. A pH of 7 indicates a balance between acidic and basic properties in a solution, making it neither acidic nor basic. Values below 7 are acidic, above 7 are basic, and 7 is the midpoint representing neutrality. Therefore, a solution with a pH of 7 is neutral.
What is the term for the reactant that is entirely consumed by the reaction?
- A. limiting reactant
- B. reducing agent
- C. reaction intermediate
- D. reagent
Correct Answer: A
Rationale: The correct answer is A, limiting reactant. In a chemical reaction, the limiting reactant is the substance that is entirely consumed when the reaction reaches completion. It determines the maximum amount of product that can be formed. The reducing agent (choice B) is a substance that donates electrons to another chemical species, the reaction intermediate (choice C) is a molecule formed and consumed in different steps of the reaction, and a reagent (choice D) is a general term for any substance participating in a chemical reaction.