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 20 of 45
- A. 4
- B. 8
- C. 2
- D. 16
Explanation: The molar volume of a gas at STP is 22.4 dm3/mol.Given:Volume of methane (V) = 11.207 dm3Molar volume at STP (Vm) = 22.4 dm3/molUsing the…
Correct answer: 2- A. 2.24dm3
- B. 22.4dm3
- C. 11.2dm3
- D. 1.24dm3
Explanation: According to Avogadro's Law and the molar mass of oxygen (O₂), which is approximately 32 g/mol, 1 mole of oxygen gas occupies 22.4 dm³ at…
Correct answer: 11.2dm3- A. All the reactants are completely converted into products
- B. No reversible reaction occurs
- C. In calculations, the law of conservation of mass and law of definite proportions are obeyed
- D. Side reaction occurs
Explanation: The correct answer is D. Side reactions occur alongside the main reaction and can alter the expected outcomes by producing additional…
Correct answer: Side reaction occurs- A. 3.01 x 10^23
- B. 6.02 x 10^23
- C. 3.01 x 10^20
- D. 6.02 x 10^24
Explanation: To find the number of moles in 6 mg, first convert mg to grams i.e 6 mg=0.006 gNow divide 0.006g by the molar mass of carbon:(0.006 g) /…
Correct answer: 3.01 x 10^20385. 24g each of carbon and oxygen react to form CO2. The amount of unreacted element left behind is:
- A. 6g
- B. 15g
- C. 16g
- D. 10g
Explanation: 1 mole combines with 1 mole of O2 to give 1 Mole of CO2.No of moles of C in 24 g = 24/12 =2 molesNo of moles of O2 in 24 g = 24/32 = 0.75…
Correct answer: 15g- A. Molar volume of the gas
- B. Molar mass of the gas
- C. NA molecules of the gas
- D. All of these
Explanation: Option A suggests that one mole of any gas represents the molar volume of the gas.
Correct answer: Molar volume of the gas- A. 1.0
- B. 0.5
- C. 0.25
- D. 0.1
Explanation: The molar mass of H2O is 18 g/mol and molar mass of O2 is 32 g/mol. To find out how many moles of O2 are in 16g, we divide given mass…
Correct answer: 1.0- A. 2.24 L.
- B. 4.48 L.
- C. 44.8 L.
- D. 48.4 L.
Explanation: Chemical reaction involved is: CaCO3 _CaO + CO2 As the reaction is balanced so 0.2 moles of calcium carbonate will produce 0.2 moles of…
Correct answer: 4.48 L.- A. Decrease to half.
- B. Increase two-fold.
- C. Decrease quarter-fold.
- D. Become fractional.
Explanation: The relative atomic mass unit is based on the mass of carbon-12. If we change the basis to 1/6th of the carbon atom's mass instead of…
Correct answer: Increase two-fold.- A. 6.02 x 10^23
- B. 1.20 x 10^24
- C. 12.04 x 10^22
- D. 6.02 x 10^24
Explanation: The correct answer is 1.20 x 1024. A mole of any substance contains Avogadro's number (6.02 x 1023) of entities, in this case, H2…
Correct answer: 1.20 x 10^24- A. Actual yield.
- B. Theoretical yield.
- C. Percentage yield.
- D. Amount of the reactant unused.
Explanation: It is a fact and statement because percentage yield is efficency percentage.
Correct answer: Percentage yield.- A. 10 %
- B. 50 %
- C. 90 %
- D. 100 %
Explanation: Actual yield is equal to theoretical yield when the reaction goes to completion and there is no loss of product so the efficiency of the…
Correct answer: 100 %- A. 3
- B. 3.5
- C. 2.0
- D. 0.5
Explanation: Moles of H2= 4/2=2 moles Moles of O2 =8/32=0.25 moles Consider the balanced chemical equation: 2H2 + O2 --------------------- 2H2O Mole…
Correct answer: 2.0- A. 23 g.
- B. 19.5 g.
- C. 39 g.
- D. 6.02 x 10^23 g
Explanation: Moles of sodium= 11.5/23= 0.5 moles. Number of sodium atoms= (0.5)(6.02 10*23) =3 10*23 atoms Mass of potassium= 39/NA (3* 1023 =19.5g
Correct answer: 19.5 g.- A. Physical chemistry
- B. Biochemistry
- C. Stoichiometry
- D. Organic chemistry
Explanation: Stoichiometry is a branch of chemistry that deals with the quantitative relationships and calculations involving the amounts of reactants…
Correct answer: Stoichiometry- A. 0.25
- B. 0.125
- C. 0.50
- D. 1.50
Explanation: The balanced chemical equation for the reaction between potassium hydroxide (KOH) and sulfuric acid (H2SO4) to produce potassium sulfate…
Correct answer: 0.125- A. 20 g
- B. 30 g
- C. 50 g
Explanation: As we know sodium has 1 valence electron while calcium has 2 valence electron so if 23g of sodium which is equal to 1 mole of sodium…
Correct answer: 20 g- A. 3.01 x 10^23
- B. 6.02 x 10^23
- C. 2.41 x 10^24
- D. 2.24 x 10^24
Explanation: Moles of H2S=mass/molar mass= 68/43= 2 moles Number of molecules= moles( NA) =2(6.02 x 1023) Number of covalent bonds=2( number of…
Correct answer: 2.41 x 10^24- A. 1:2
- B. 1:8
- C. 1:1
- D. 2:1
Explanation: At STP, 1 mole of any ideal gas occupies 22.4 liters. The molar mass of H2 is 2 g/mol, so 4 g of H2 is 2 moles, which occupies 2 x 22.4 =…
Correct answer: 1:1- A. 32 g
- B. 3.2 g
- C. 5.6 g
- D. 9.6 g
Explanation: Balanced Chemical Equation:C2H5OH +3O2 ----------- 2CO2 + 3H2OFrom balanced chemical equation, the ratio between C2H5OH and O2 is 1:3.
Correct answer: 9.6 g