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 3 of 45
- A. 63.012 g/mol
- B. 65.012 g/mol
- C. 70.012 g/mol
- D. 81.011 g/mol
Explanation: Using standard atomic masses, the molar mass of HNO3 is 1.008 g/mol + 14.007 g/mol + 3 x 15.999 g/mol = 63.012 g/mol.
Correct answer: 63.012 g/mol- A. 0.1 M
- B. 1 m
- C. 1 M
- D. 0.1 N
Explanation: The molar mass of NaCl is 58.5 g mol−1, so 58.5 g represents 1 mol. Since this amount is present in 1 dm3 of solution, molarity = 1 mol /…
Correct answer: 1 M- A. 180g/dm3
- B. 170g/dm3
- C. 190g/dm3
- D. 195g/dm3
Explanation: A 1 molar solution contains 1 mol of solute in 1 dm3 of solution. Glucose has molar mass 180 g mol−1, so mass = 1 mol dm−3 × 180 g mol−1 =…
Correct answer: 180g/dm3- A. normality
- B. molarity
- C. molality
- D. mole fraction
Explanation: Molality is defined as the number of moles of solute present in 1 kg of solvent, with units mol kg−1.
Correct answer: molality- A. Value of a
- B. Mass
- C. Atoms
- D. Both B and C
Explanation: Each sample contains 0.5 mol of molecules, so both have 0.5 x 6.022 x 10^23 = 3.011 x 10^23 molecules.
Correct answer: Both B and C- A. Quantitative analysis
- B. Qualitative analysis
- C. Stochiometery
- D. Physical chemistry
Explanation: Quantitative analysis determines the amount or concentration of each component in a sample, using measurements and calculations.
Correct answer: Quantitative analysis- A. Stoichio chemistry
- B. Physical chemistry
- C. Analytical chemistry
- D. Quantum chemistry
Explanation: Analytical chemistry includes both qualitative analysis, which identifies components, and quantitative analysis, which measures their…
Correct answer: Analytical chemistry- A. 6.022 x 10^23
- B. 3.01 x 10^23
- C. 2 x NA
- D. 4 x 6.022 x 10^23
Explanation: The molar mass of NaCl is 23.0 g/mol + 35.5 g/mol = 58.5 g/mol. Thus 29.25 g ÷ 58.5 g/mol = 0.5 mol, and 0.5 mol x 6.022 x 10^23 formula…
Correct answer: 3.01 x 10^23- A. macromolecule
- B. macromolecule
- C. molecularity
- D. atomicity
Explanation: Atomicity is the number of atoms present in one molecule of an element or compound, such as two atoms in O2 or three atoms in O3.
Correct answer: atomicity- A. 22.4 dm3
- B. 2.24 dm3
- C. 1.12 cm3
- D. 1.12 dm3
Explanation: The molar mass of CO is 12 g mol-1 + 16 g mol-1 = 28 g mol-1. Thus 1.4 g ÷ 28 g mol-1 = 0.050 mol, and at STP its volume is 0.050 mol x…
Correct answer: 1.12 dm3- A. moles dm-3
- B. moles kg-1
- C. gram dm-3
- D. none
Explanation: Molality is defined as the number of moles of solute dissolved in 1 kilogram of solvent, so its unit is moles kg-1.
Correct answer: moles kg-1- A. identification of elements
- B. estimation of amounts of elements
- C. molar ration of elements
- D. molar volume of elements
Explanation: Qualitative analysis answers the question of what is present, so it is used to identify the elements or ions in a sample.
Correct answer: identification of elements- A. 1.008 mg
- B. 0.184 mg
- C. 0.054 mg
- D. 5.4 mg
Explanation: The mass of one electron is about 9.11 x 10^-31 kg, so the mass of 0.1 mol of electrons is 0.1 x 6.022 x 10^23 x 9.11 x 10^-31 kg = 5.49 x…
Correct answer: 0.054 mg- A. relative atomic mass
- B. mass number
- C. atomic weight
- D. relative isotopic mass
Explanation: The value 35.5 is the weighted average relative atomic mass of naturally occurring chlorine isotopes, mainly 35Cl and 37Cl.
Correct answer: relative atomic mass- A. 1.6 x 10^-27 kg
- B. 1.6 x 10^-24 kg
- C. 1.6 x 10^-26 kg
- D. 1.6 x 10^-28 kg
Explanation: One atomic mass unit is defined as approximately 1.66 x 10^-27 kg, which is rounded in the options to 1.6 x 10^-27 kg.
Correct answer: 1.6 x 10^-27 kg56. The properties of an element mosly corresponds to that isotope which has greater_________________?
- A. Mass number
- B. Atomic mass
- C. Relative abundance
- D. all of the above
Explanation: An element's observed atomic properties usually reflect the isotope that occurs in the greatest relative abundance, because that isotope…
Correct answer: Relative abundance- A. NaCl
- B. H2O
- C. CCI4
- D. It can be applied to all mentioned above
Explanation: An empirical formula gives the simplest whole-number ratio of atoms. NaCl is already in its simplest ratio, H2O cannot be reduced, and…
Correct answer: It can be applied to all mentioned above- A. lighter
- B. intermediate
- C. heavier
- D. are collected at same time
Explanation: In a magnetic field, charged particles with lower mass-to-charge ratio are deflected more strongly, so lighter cationic molecular ions…
Correct answer: lighter- A. different number of protons
- B. same number of neutrons
- C. different number of neutrons
- D. same mass number (nucleon number)
Explanation: Isotopes are atoms of the same element, so they have the same number of protons but different numbers of neutrons.
Correct answer: different number of neutrons- A. Mass of an atom itself is in fraction
- B. Atomic masses are average masses of isobars
- C. Atmoic masses are average masses of isotopes proportional to their relative abundance
- D. Atmoic masses are average masses of isotopes
Explanation: The atomic mass of an element is a weighted average of the masses of its naturally occurring isotopes, with each isotope weighted…
Correct answer: Atmoic masses are average masses of isotopes proportional to their relative abundance