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.
Last updated
Read the Fundamental Concepts of Chemistry notesFree MDCAT chapter notes with key terms894 questions · page 5 of 45
- A. 154
- B. 280
- C. 86
- D. 300
Explanation: Total number of isotopes is 280. Out of 280 isotopes 154 have even mass or even atomic no. and 86 have odd atomic mass or no
Correct answer: 86- A. 0.5
- B. .01
- C. 1.5
- D. 2.0
Explanation: Phosphoric acid (H₃PO₄) dissociates in aqueous solution into three moles of hydrogen ions H+ and one mole of phosphate ions (PO4)3- .
Correct answer: 2.0- A. NaCl
- B. H₂O
- C. (c) CCl₄
- D. Can be applied to all of the above
Explanation: The term empirical formula can be applied to all the compounds listed. The empirical formula represents the simplest whole-number ratio of…
Correct answer: Can be applied to all of the above- A. 5
- B. 4
- C. 3
- D. 2
Explanation: Dempster's mass spectrometer is a type of mass spectrometer that is designed with four main zones or parts to perform its…
Correct answer: 4- A. Mass number
- B. Atomic mass
- C. Relative Abundance
- D. All of above
Explanation: This is because the abundance of isotopes in nature affects the overall behavior and properties of the element.
Correct answer: Relative Abundance- A. Mass of atom is itself reactional
- B. Atomic masses are average masses of isobars
- C. Atomic masses are average masses of isotopes
- D. Atomic masses are average masses of isotopes proportional to their abundance
Explanation: Atomic masses are typically reported as weighted averages that take into account the abundance of each isotope of an element.
Correct answer: Atomic masses are average masses of isotopes proportional to their abundance- A. 3.49 x 10⁻²⁴
- B. 2.53 x 10²⁴
- C. 1.26 x 10²⁴
- D. 3.79 x 10²⁴
Explanation: Since there are 2.1 moles of CO₂, we can easily find out the number of molecules present in it by multiplying 2.1 with the Avagadro's…
Correct answer: 1.26 x 10²⁴- A. 165.6 g
- B. 157 g
- C. 148 g
- D. 138 g
Explanation: Moles = Mass / molar mass Moles x molar mass = mass in grams Molar mass of phosphoric acid H₃PO₄ = 98 g / mol 1.69 mol x 98 g /mol = mass…
Correct answer: 165.6 g- A. Ultraviolet radiations
- B. Visible radiation
- C. Infrared radiation
- D. All of these
Explanation: Spectroscopy is a method of understanding molecules by measuring the interaction of light and matter.
Correct answer: All of these- A. 0.1, 0.2
- B. 0.1, 0.3
- C. 0.2, 0.4
- D. 0.2, 0.1
Explanation: The mole is a SI unit of measurement that is used to calculate the quantity of any substance.
Correct answer: 0.2, 0.1- A. 1.4 moles
- B. 2.4 moles
- C. 2 moles
- D. 1.2 moles
Explanation: 1 mole of metal formed one mole of MF2 molecule ∴ 0.7 mole of metal formed = 0.7 mole MF2 molecule ∵ Each molecule of MF2 contains = 2F…
Correct answer: 1.4 moles- A. 1 x 10^-28 kg to 1 x 10^-22 kg
- B. 1 x 10^-26 kg to 1 x 10^-23 kg
- C. 1 x 10^-27 kg to 1 x 10^-24 kg
- D. 1.6373 x 10^-27 kg to 1 x 10^-25 kg
Explanation: Mass of an atom ranges from 1 x 10-27 to 1 x 10-25 .Thus, option D is correct.
Correct answer: 1.6373 x 10^-27 kg to 1 x 10^-25 kg- A. 14
- B. 16
- C. 18
- D. 2
Explanation: Since we know that 18 moles of water are produced alongside carbon dioxide.
Correct answer: 1694. If the number of molecules of different gases are the same at S.T.P., the occupied volume will be _:
- A. Greater
- B. Same
- C. Smaller
- D. Twice
Explanation: At standard temperature and pressure, 1 mole of gas has a volume of 22.4 dm3.
Correct answer: Same- A. Size
- B. Position
- C. Shape
- D. Structure
Explanation: D is correct as in "Mass Spectrometry", large molecules are broken down into smaller unstable ions in the Ionization Chamber.
Correct answer: Structure- A. 1nm
- B. 0.2nm
- C. 3nm
- D. 4nm
Explanation: X-ray work in the 20th century showed that the diameter of atoms are of order of 0.2 nm.
Correct answer: 0.2nm- A. Under similar conditions of temperature and pressure, gases react with each other in simple ratio.
- B. Under similar conditions of temperature and pressure, equal volumes of all gases contain same number of molecules.
- C. At NTP all gases contain same number of molecules.
- D. Gases always react with gases only at given temperature and pressure.
Explanation: Avogadro's hypothesis states that equal volumes of gases at the same temperature and pressure contain the same number of particles…
Correct answer: Under similar conditions of temperature and pressure, equal volumes of all gases contain same number of molecules.- A. 3.6g of H2
- B. 4.8g of C2H5OH
- C. 2.8g of CO
- D. 5.4g of N2O5
Explanation: Using the formulas; Moles = mass in (g) / Mr no.of molecules = moles× Avogadro's constant. Moles= 5.4/108 = 0.05 mol No.
Correct answer: 5.4g of N2O5- A. Conservation of mass
- B. Definite proportion
- C. Both A and B
- D. None of these
Explanation: In stoichiometry , the law of conservation of mass and law of definite proportions are obeyed.
Correct answer: Both A and B- A. All gases
- B. Inert gases
- C. Ideal gases
- D. Light gases
Explanation: Avogadro's law states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.
Correct answer: Ideal gases