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 34 of 45
- A. 4 x 6.022 x 10^23
- B. 2 x 6.022 x 10^23
- C. 1 x 6.022 x 10^23
- D. 2 x 6.022 x 10^22
Explanation: Option D is correct.When 0.1 mole of sulfuric acid is completely ionized in water, it will produce 2 x 6.022 x 10^22 H+ ions.Sulfuric acid…
Correct answer: 2 x 6.022 x 10^22- A. 200
- B. 300
- C. 1800
- D. 180
Explanation: Option C is correct.The explanation is given in image.
Correct answer: 1800- A. 1 mole
- B. 2 moles
- C. 0.5 moles
- D. 0.25 moles
Explanation: Moles of H2 to be produced: Mole = Volume / Volume at STP = 11.212 / 22.14 = 0.50mol According to the equation the ratio of moles of Mg…
Correct answer: 0.5 moles- A. 6.4 g
- B. 1.6 g
- C. 46 g
- D. 16 g
Explanation: The mass of 0.25 moles of SO2 is 16 grams.The molar mass of SO2 is 64.0668 grams per mole.
Correct answer: 16 g- A. C4H8
- B. C4H9OH
- C. C5H11OH
- D. C5H12
Explanation: The formula of the compound with a maximum of 8 moles of oxygen gas required for complete oxidation is C5H12.The combustion reaction for…
Correct answer: C5H12- A. 10 cm3
- B. 15 cm3
- C. 20 cm3
- D. 25 cm3
Explanation: CH4 + 2O2 → CO2 + 2H2O C2H4 + 3O2 → 2CO2 + 2H2O In these reactions, 1 mole of CH4 requires 2 moles of oxygen and 1 mole of C2H4 requires 3…
Correct answer: 25 cm3- A. 0.4 moles
- B. 0.3 moles
- C. 0.2 moles
- D. None of these
Explanation: Molar mass of Na2CO3 = 106 g/mole Moles of Na2CO3 in 10.6g = mass/molar mass = 10.6g/106 g/mole = 0.1 moles.
Correct answer: 0.3 moles- A. 1 g.
- B. 2 g.
- C. 4 g.
- D. 8 g.
Explanation: One mole of helium(1NA) has a mass of 4g. Two moles of helium(2NA) has a mass of 8g.
Correct answer: 8 g.- A. 6.02 x 10^23
- B. 1.20 x 10^25
- C. 1.204 x 10^24
- D. 6.02 x 10^24
Explanation: 1 mole of hydrogen gas contain 6.022 molecule and each molecule contain 2 proton so 2NA =2*6.022 1023 =1.204*1024
Correct answer: 1.204 x 10^24- A. 2.4 x 10^24
- B. 3.6 x 10^26
- C. 1.2 x 10^25
- D. 4.8 x 10^26
Explanation: Molar mass of water= 18g/mol.Convert the total mass to grams=10.8kg =10800g Calculate the moles of water=10800/18 =599.89 moles.
Correct answer: 3.6 x 10^26- A. 11.2 dm3 of H2 gas at STP.
- B. 44.8 dm3 of N2 gas at STP.
- C. 67.2 dm3 of CO2 gas at STP.
- D. 22.4 dm3 of O2 gas at STP.
Explanation: In option C, 67.2 dm3 of CO2 is equal to 3 moles which is maximum in the given options. Hence option C is correct.
Correct answer: 67.2 dm3 of CO2 gas at STP.- A. Isotopes.
- B. A half proton.
- C. A half neutron
- D. A half electron.
Explanation: The Half number in relative atomic mass of Chlorine (i.e 35.5) is due to two naturally occurring isotopes (Chlorine-35 and Chlorine-37).
Correct answer: Isotopes.- A. 11
- B. 23
- C. 12
- D. 22
Explanation: The atomic number represents the number of protons in the nucleus, so if atomic number is 11 it means number protons is 11.
Correct answer: 11- A. SO
- B. SO2
- C. SO3
- D. SO4
Explanation: S : O 50/32 : 50/16 1.5 : 3 1.5/1.5 : 3/1.5 1 : 2
Correct answer: SO2- A. Chemical change.
- B. Physical change.
- C. Neither chemical nor physical change.
- D. Both physical and chemical.
Explanation: 2 KOH + CO₂ → K₂CO₃ + H₂O It is a chemical change because it involves breaking and forming new chemical bonds.
Correct answer: Chemical change.- A. C3H404.
- B. C2H2O.
- C. C2H2O4.
- D. C2HO2.
Explanation: C : H : O 34.6/12 :3.5/1 : 61.5/16 3 : 4 : 4 => E:F= C3H4O4 =>E.F.Mass= (3x12)+(1x4)+(4x16) = 104 => n= Molecular Mass/ E.F.Mass = 104/104…
Correct answer: C3H404.- A. Ionic formula.
- B. Structural formula.
- C. Empirical formula.
- D. Molecular formula.
Explanation: It shows the simplest ratio for the atoms of different elements in a compound.
Correct answer: Empirical formula.- A. C9H18O9.
- B. CH2O.
- C. C6H12O6.
- D. C2H4O2.
Explanation: =>E.F: CH2O => Empirical formula mass= (1x12)+(2x1)+(1x16) = 30 => n= Molecular Mass/E.F.Mass =180/30= 6 => Molecular formula= n x E.F = 6…
Correct answer: C6H12O6.- A. 250 ml
- B. 125 ml
- C. 166.67 ml
- D. 111.11 ml
Explanation: Following is the solution to this question:
Correct answer: 166.67 ml680. The concentration of C = 85.45% and H = 14.55% is not obeyed by which of the following formula:
- A. CH2
- B. C2H4
- C. C2H6
- D. C4H8
Explanation: C2H6 (ethane) does not obey the given percentage composition. The calculated carbon percentage is 20%, which is significantly lower than…
Correct answer: C2H6