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 25 of 45
- A. NH3
- B. N2H4
- C. NO
- D. NH4OH
Explanation: Mr of N2H4= (2x14) + (4x1) = 32% by mass of Nitrogen= 2x14/32 x100 = 87.5%
Correct answer: N2H4- A. 27.27%
- B. 40%
- C. 30.8%
- D. 60%
Explanation: Mr of CO2= 12 + (2x16) = 44% by mass of Carbon = 12/44 x100 = 27.27
Correct answer: 27.27%- A. 28
- B. 42
- C. 58
- D. 68
Explanation: Mr of Ca(NO3)2= 40 + (2x14) + (6x16) = 164% by mass of Oxygen = 6x16/164 x100 = 58.53
Correct answer: 58- A. Irreversible reaction
- B. Reversible reaction
- C. Exothermic
- D. Endothermic
Explanation: The reactant that is consumed completely in a chemical reaction is called limiting reactant.As in irreversible reactions the yield of…
Correct answer: Irreversible reaction- A. 4 moles of C
- B. 5 moles of C
- C. 8 moles of C
- D. None of these
Explanation: The stoichiometric coefficients tell us the molar ratios between the reactants and products.
Correct answer: 4 moles of C- A. 100dm3
- B. 50dm3
- C. 60dm3
- D. 70dm3
Explanation: The balanced chemical equation is 2CO + O2 → 2CO2, which indicates that 2 volumes of CO react with 1 volume of O2.
Correct answer: 100dm3- A. Sulphur
- B. Fluorine
- C. Both a and b
- D. None of these
Explanation: The balanced chemical equation is as followS + 3F2 => SF61 S => 1 SF64 S => x SF6x= 4 SF63 F2 => 1SF620 F2 => xSF6x= 20/3 SF6As more moles…
Correct answer: Fluorine- A. 24.5g H2SO4
- B. 13.5g 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. 50 g
- B. 72 g
- C. 36 g
- D. 54 g
Explanation: This answer is incorrect because the number of moles of water produced is not 3.
Correct answer: 72 g- A. Inhibitor
- B. Limiting reactant
- C. Catalyst
- D. Non-limiting reactant
Explanation: The limiting reactant is the reactant that is consumed completely first hence limits the reaction from proceeding leading to production of…
Correct answer: Limiting reactant- A. 2
- B. 8
- C. 10
- D. 13
Explanation: The balanced chemical equation for the reaction is as follow 2 C4H10 + 13 O2 => 8 CO2 + 10 H2OFirst of all to construct a balanced…
Correct answer: 13- A. Amount of limiting reactant
- B. Amount of reactant in excess
- C. Amount of product formed
- D. Amount of reactant left unused
Explanation: The efficiency of a chemical reaction can assessed by calculating the amount of product formed because it provides a measure of how…
Correct answer: Amount of product formed- A. CaCO3 is the limiting reagent
- B. Both reactants are consumed completely
- C. HCl is the limiting reagent
- D. There is no reaction
Explanation: The equation for the reaction isCaCO3 + 2HCl → CO2 + H2O + CaCl2Mr of HCl= 1 + 35.5 = 36.5Mr of CaCO3= 40 + 12 + (3x16) = 1002x36.5g of…
Correct answer: CaCO3 is the limiting reagent- A. C3H4
- B. C6H5
- C. C7H8
- D. C2H4
Explanation: Mr of H2O= 18g/molMr of CO2= 44g/molMole of H2O= 0.72/18 = 0.04molMole of CO2= 3.08/44 = 0.07molFor a balanced chemical equation for…
Correct answer: C7H8- A. 1.5
- B. 11.2
- C. 3
- D. 6
Explanation: 1mol => 22.4dm3 at STPxmol => 11.2dm3 at STPx= 0.5molSO2+2H2S---2H2O+3S1mol. 2mol. 3mol0.5mol 2mol.
Correct answer: 1.5- A. 1.2 moles of H2O are produced
- B. All the oxygen is consumed
- C. 0.8 moles of NO is formed
- D. Some ammonia remains unreacted
Explanation: 4NH3 => 5O2xNH3 => 1O2x= 0.8molAs oxygen is the limiting factor it will be consumed first.
Correct answer: All the oxygen is consumed- A. 58%
- B. 70%
- C. 50%
- D. 90%
Explanation: Mr of 1-propanol= 60g/molMr of 1-bromopropane= 122.9g/mol60g => 122.9g10g => xgx= 20.5Percentage Yield = (Actual Yield / Theoretical…
Correct answer: 58%- A. Actual yield
- B. Percentage yield
- C. Theoretical yield
- D. None
Explanation: Theoretical yield is the maximum amount of product that can be obtained from a given amount of reactant, assuming that the reaction goes…
Correct answer: Theoretical yield- A. Reversibility of reaction
- B. Inexperienced worker
- C. Competing side reaction
- D. All of the above
Explanation: This answer is correct as all the above options effects the yield of a chemical reaction hence this is the best possible option.
Correct answer: All of the above- A. 75%
- B. 81.81%
- C. 50%
- D. 95%
Explanation: Mr of CH4= 12 + (4x1) = 16g/molMr of CO2= 12 + (2x16) = 44g/molCH4 + 2O2 → CO2 + 2H2O16g => 44g8g => xgx= 22Percentage yield = (Actual…
Correct answer: 81.81%