Free Fundamental Concepts of Chemistry MCQs with Answers
894 Fundamental Concepts of Chemistry MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.
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Read the Fundamental Concepts of Chemistry notesFree MDCAT chapter notes with key terms894 questions · page 37 of 45
- A. High energy trelecon beam
- B. α-particle
- C. X-rays
- D. All of the above
Explanation: Molecular ions are formed by passing high-energy electrons through a sample .High-energy electrons can ionize molecules by knocking off…
Correct answer: High energy trelecon beam- A. Relative abundance
- B. Average mass of the element
- C. Number of isotopes
- D. Relative isotopic mass
Explanation: The number of peaks obtained in mass spectrometry corresponds to the number of isotopes of the element present in the sample.
Correct answer: Number of isotopes- A. CH₂Cl₂
- B. CH₃Cl
- C. CCl₄
- D. CHCl₃
Explanation: Empirical formula gives the simplest whole-number ratio of atoms in a molecule.
Correct answer: CHCl₃- A. Isotopes with odd atomic number are abundant
- B. Isotopes with odd atomic number and even mass number are abundant
- C. Isotopes with even atomic number and even mass number are abundant
- D. Isotopes with even atomic number and odd mass number are abundant
Explanation: Isotopes with even atomic number and even mass number are abundant.There are several reasons why isotopes with even atomic numbers and…
Correct answer: Isotopes with even atomic number and even mass number are abundant- A. 2.24dm3
- B. 22.4 dm³
- C. 1.12 dm³
- D. 11.2 cm³
Explanation: To find the volume occupied by a gas at Standard Temperature and Pressure (STP), we can use the ideal gas law and the molar volume of a…
Correct answer: 2.24dm3- A. 0.25
- B. 0.50
- C. 0.75
- D. 100
Explanation: One mole of CO2 has a mass of 44 g and 32 g of O2.So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.Therefore, the mathematical…
Correct answer: 0.50- A. They possess different mass numbers
- B. They possess different physical properties
- C. They possess the same chemical properties
- D. They possess different positions in the periodic table
Explanation: This statement is incorrect. Isotopes of the same element share the same position on the periodic table because they have the same number…
Correct answer: They possess different positions in the periodic table- A. identification of elements
- B. Estimation of amounts of elements
- C. Molar ratio of elements
- D. Molar volume of elements
Explanation: Qualitative analysis is a branch of analytical chemistry that is concerned with identifying the elements or compounds present in a sample.
Correct answer: identification of elements- A. mass of an atom itself is in fraction
- B. atomic masses are average masses of isobars
- C. atomic masses are average masses of isotopes proportional to their relative abundance
- D. atomic masses are average masses of isotopes
Explanation: Most elements exist as a mixture of isotopes, each with a slightly different mass due to variations in the number of neutrons.
Correct answer: atomic masses are average masses of isotopes proportional to their relative abundance730. Isotopes differ in
- A. properties which depend upon mass
- B. The arrangement of electrons in orbitals
- C. chemical properties
- D. All of the above
Explanation: Isotopes of an element have the same number of protons (same atomic number), which means they belong to the same chemical element and have…
Correct answer: properties which depend upon mass- A. Sand
- B. Hemoglobin
- C. Diamond
- D. Maltose
Explanation: A macromolecule is a large, complex molecule typically formed by the polymerization of smaller subunits. Sand is not a macromolecule.
Correct answer: Sand- A. Combustion method
- B. Duma's method
- C. Kjeldahl's method
- D. All of the above methods are for different purposes
Explanation: The combustion method is a commonly used technique to estimate the percentage of carbon and hydrogen in an organic compound.
Correct answer: Combustion method- A. High energy electron beam
- B. ∝-particle
- C. X-rays
- D. All of the above
Explanation: Molecular ions are formed by passing high energy electron beam, X-rays or α-particles: Passing a high-energy electron beam through a…
Correct answer: All of the above- A. sea water
- B. brass
- C. tape water
- D. graphite
Explanation: A substance is defined as matter that has a specific composition and distinct properties.Graphite - Graphite is a form of carbon.
Correct answer: graphite- A. Are always different
- B. Are always similar
- C. May be similar or different
- D. Ionic compound do not have any empirical formula
Explanation: The relationship between the empirical formula and formula unit of an ionic compound depends on the individual compound and its structure.
Correct answer: May be similar or different- A. 1.2 x 10 23
- B. 6 x 10^22
- C. 6 x 10^2
- D. 12 x 10^2
Explanation: To determine the number of oxygen atoms in a given mass of carbon dioxide (CO2 ), you can use the following steps:Find the moles of CO2…
Correct answer: 1.2 x 10 23- A. 3.6g of water
- B. 4.4g of C2H5OH
- C. 2.8g of CO
- D. 5.4g of N2O2
Explanation: To find the largest number of molecules, we need to calculate the number of moles for each substance.
Correct answer: 3.6g of water- A. 0.32g
- B. 0.64g
- C. 0.16g
- D. 0.96
Explanation: Here's how to find the weight of liquefied oxygen:Convert volume to moles:○ We need to convert the volume of oxygen from milliliters (mL)…
Correct answer: 0.16g- A. 1.008g of H has 6.02 x 10^23 atoms
- B. 2.016g of H2 has 2 x 6.02 x 10^23 atoms
- C. 1.008g of H2 has 6.02 x 10^23 atoms
- D. Both Options A and B are correct
Explanation: 1 mole of any substance contains Avogadro's number of particles, which is approximately 6.02 x 10^23.The molar mass of H2 (molecular…
Correct answer: 1.008g of H2 has 6.02 x 10^23 atoms- A. 6.022 x 10²³ / 1.0 x 10⁻⁶
- B. 1.0 x 10⁻⁶ x 6.022 x 10²³ / 20.2
- C. 1.0 x 10⁻⁶ x 6.022 x 10²³
- D. 1.0 x 10⁻⁶ x 6.022 x 10²³ / 9.65 x 10⁴
Explanation: To ionize each Ne atom to a Ne⁺ ion, one electron is removed per atom. Therefore, the total number of electrons to remove is equal to the…
Correct answer: 1.0 x 10⁻⁶ x 6.022 x 10²³