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 39 of 45
- A. 24.5g H2SO4
- B. 20g NaOH
- C. 46.5g NaOH
- D. 60g NaOH
Explanation: Mr of NaOH= 23 + 16 + 1 = 40g/molMr of H2SO4= (2x1) + 32 + (4x16) = 98g/mol2NaOH + H2SO4 => Na2SO4 +2H2O2x40g. 98g. xg.
Correct answer: 46.5g NaOH- A. 6.2 x 10^22
- B. 6.22 x 10^22
- C. 6.02 x 10^23
- D. 6.02 x 10^22
Explanation: Avogadro's law states that in one mole of any substance, a total number of 6.023×1023 molecules are present.
Correct answer: 6.02 x 10^23763. When 8 grams (4 moles) of H2 react with 2 moles of O2 , how many moles of water will be formed?
- A. 5
- B. 4
- C. 6
- D. 3
Explanation: The balanced chemical equation for the reaction between hydrogen gas and oxygen gas to form water is:2H2 + O2 → 2H2OFrom the equation, we…
Correct answer: 4- A. Operational losses
- B. Reaction reversibility
- C. Side reaction
- D. All of these options are correct
Explanation: Usually, the actual yield is lower than the theoretical yield because few reactions truly proceed to completion (i.e., aren't 100%…
Correct answer: All of these options are correct- A. Reactant
- B. Products
- C. Both Options A and B are correct
- D. None of these options are correct
Explanation: The limiting reactant is the one that gets consumed first in a chemical reaction.
Correct answer: Products- A. Always conform to the valency rules
- B. Always have a subscript of 1 for the first element
- C. Always have a subscript of 2 for the second element
- D. Always be written in alphabetical order of the elements
Explanation: This is the correct answer. A correct chemical formula must always conform to the valency rules.
Correct answer: Always conform to the valency rules- A. 25 NA
- B. 1.1 NA
- C. 2.5 NA
- D. 0.5 NA
Explanation: The Protium (hydrogen isotope) does not have any neutrons. We assume a deuterium isotope that has one neutron.
Correct answer: 2.5 NA- A. Rate of reaction
- B. Physical states of reactants and products.
- C. Conditions
- D. Both A & C
Explanation: Chemical equations involve the elements involved in a reaction, the number of molecules of the elements, the state symbols.
Correct answer: Both A & C- A. Chlorine
- B. Hydrogen
- C. Flourine
- D. Cadmium
Explanation: The number of isotopes of the following elements are: Chlorine 2 Hydrogen 3 Fluorine 1 Cadmium 11
Correct answer: Flourine- A. It is counting unit
- B. It is the gram atomic or gram formulae mass of a substance
- C. It contains 6.023 x 10^23 particles
- D. It contains different number of particles for different substances
Explanation: Option d is correct because moles represent a quantity of substance, and this quantity will differ for different substances due to their…
Correct answer: It contains different number of particles for different substances- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The balanced chemical equation is 3Mg+2NH3→Mg3N2+3H2 48 g of magnesium will react with (48×2×17)/(24×3)=22.67 g of ammonia.
Correct answer: Option A- A. 1 mg of C4H10
- B. 1 mg of N2
- C. 1 mg of Na
- D. 1 ml of H2O
Explanation: Following is the solution to this question:
Correct answer: 1 ml of H2O- A. 32 g
- B. 41.2 g
- C. 80
- D. 156 g
Explanation: Following is the solution to this question:To find the molecular mass of the alcohol, we can use the formula:Molecular mass = (Mass of…
Correct answer: 80- A. 0.1 mol and 0.3 mol
- B. 0.05 mol and 0.3 mol
- C. 0.05 mol and 0.15 mol
- D. 0.1 mol and 0.15 mol
Explanation: First, form a balanced equation of the reaction.KIO3 + 2 KI + 6 HCl → 3 ICl + 3 KCl + 3 H2OCalculate the moles of KI used Mass of KI =…
Correct answer: 0.05 mol and 0.15 mol- A. 68000 times
- B. 17000 times
- C. 34000 times
- D. 1700 times
Explanation: Mass of Hb compared to H/Molar mass of Helium 68000/4= 17000
Correct answer: 17000 times- A. 25 g of iodine
- B. 25 g atoms of oxygen
- C. 25 g moles of water
- D. 25 g of nitrogen gas
Explanation: Mass of I2 = 25 g mass of O atoms= 25 x 16= 400 g mass of H2O = 25 x 18= 450 g mass of N2 gas= 25 g So, H20 has the maximum mass.
Correct answer: 25 g moles of water- A. 2.24dm3
- B. 22.4dm3
- C. 112cm3
- D. 1.12 dm3
Explanation: No. Of moles (n) = mass/ M.mass=4.4/44 = 0.1 mole Volume = n x 22.414 dm3 = 0.1 x 22.414=2.24 dm3
Correct answer: 2.24dm3- A. It is counting unit
- B. It is the gram atomic or gram formula mass of a substance
- C. It contains 6.023 x 10^23 particles
- D. It contains different number of particles for different substances
Explanation: 1 mole of any substance contains equal No. of particle i.e. 6.02x1023
Correct answer: It contains different number of particles for different substances- A. H20
- B. C6H6
- C. H2O2
- D. NaCI
Explanation: Ionic compoundsdo not have molecule rather they have formula unit (Empirical formula) so they don't have molecular formula but have…
Correct answer: NaCI- A. Mg
- B. HCI
- C. Both are in stoichiometric amounts
- D. MgCl2
Explanation: If equal masses of reactants are given then the reactant whose larger molar mass is used in balance chemical equation is limiting reactant…
Correct answer: Mg