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 Β· page 6 of 45
- A. 200 times lesser
- B. 300 times less
- C. 300 times greater
- D. 200 times greater
Explanation: In the gaseous state the distance between the molecules is 300 times greater than their diameters.
Correct answer: 300 times greater- A. 0.4 moles
- B. 0.3 moles
- C. 0.2 moles
- D. None of the given options
Explanation: 10.6/106 = 0.1 mol 3 oxygen atoms are present so: 0.1 x 3 = 0.3 mol Hence, option B is correct.
Correct answer: 0.3 moles- A. 21 grams
- B. 19 grams
- C. 18 grams
- D. 15 grams
Explanation: 8/16 = 0.5 mol of CH4 1 mole of CH4 yields 2 moles of H2O, so 0.5 mole will yield 1 mole of H2O.
Correct answer: 18 grams- A. C2H4Cl
- B. C4H8Cl
- C. C2H4Cl2
- D. C2H3Cl3
Explanation: Empirical formula mass = 12 + 2 + 35.5 = 49.5g n = 99/49.5 = 2 2 x (CH2Cl) = C2H4Cl2 Option C is the correct answer
Correct answer: C2H4Cl2- A. 8.324 atm dm-3 mol-1
- B. 0.0821 cal K-1 mol-1
- C. 0.0821 atm dm3 K-1 mol-1
- D. 8.314 cal K-1 mol-1
Explanation: At STP one mole of a gas occupies 22.4 dm3 and the value of R is 0.0821 atm dm3 K-1 mol-1.
Correct answer: 0.0821 atm dm3 K-1 mol-1- A. 22.4 ππ3
- B. 12.0 ππ3
- C. 11.2 ππ3
- D. 24.0 ππ3
Explanation: moles of Li2CO3= mass/Mr =33.5/67 = 0.5 Moles of CO2: moles of Li2CO3 1 : 1 Hence moles of CO2 =0.5 0.5 Γ 24= 12dm3 Molar volume at ROOMβ¦
Correct answer: 12.0 ππ3- A. 1.74g
- B. 21.75g
- C. 2.74g
- D. 29 g
Explanation: To calculate the mass of the product produced, you can use the yield percentage.
Correct answer: 21.75g- A. Chlorine molecules in 35.5g of chlorine gas
- B. Electrons in 1g of Hydrogen gas
- C. Hydrogen ions in 1 dm3 of 1 moldm-3 aqueous sulphuric acid
- D. Oxygen atoms in 22.4 dm3of oxygen gas at STP
Explanation: 1g Hydrogen is equal to one-mole hydrogen atom and each atom of hydrogen contains one electron so there will be one-mole electron.
Correct answer: Electrons in 1g of Hydrogen gas- A. 55ml
- B. 58ml
- C. 70ml
- D. 79ml
Explanation: Ο=0.7893g/ml n=1.2 mole The molar mass of ethanol= 46 Weight of ethanol=? Volume=?
Correct answer: 70ml- A. 2 x 10^4 molecules
- B. 4 x 10^4 molecules
- C. 4 x 10^2 molecules
- D. None of these options are correct
Explanation: At the same temperature and pressure, equal volume of the gas contains equal number of molecules.
Correct answer: 4 x 10^4 molecules- A. 0.8 L.
- B. 0.5 L.
- C. 0.4 L.
- D. 0.112 L.
Explanation: The working for the above question is as follows:We know that the volume of 1 mole of any gas at STP is 22.4 L.
Correct answer: 0.112 L.- A. NH4+
- B. H3O+
- C. NH3+
- D. SO4 2-
Explanation: A molecule containing a positive or negative charge is known as a molecular ion.
Correct answer: NH3+- A. 0.1 mol and 0.3 mol
- B. 0.03 mol and 0.1 mol
- C. 0.05 mol and 0.15 mol
- D. 0.1 mol and 0.15 mol
Explanation: First, calculate the number of moles of KI given its mass: Moles of KI = Mass (g) / Molar Mass (g/mol) Moles of KI = 16.6g / (39.1 g/mol +β¦
Correct answer: 0.03 mol and 0.1 mol- A. 32g
- B. 41.2g
- C. 82.4g
- D. 156g
Explanation: Step 1: Calculate the number of moles of gas produced at STP. The molar volume of a gas at STP is 22.4 L/mol.
Correct answer: 82.4g- A. Chemical change
- B. Neither chemical nor physical change
- C. Physical change
- D. CO2 absorbed in Mg(CLO4)2
Explanation: During combustion analysis, CO2 is chemically absorbed in 50% KOH.
Correct answer: Chemical change- A. 50% KOH solution
- B. Mg(CLO4)2
- C. 5% KOH
- D. Silica gel
Explanation: During combustion analysis, CO2 is chemically absorbed in 50% KOH. While H2O vapors are physically absorbed in Mg(CLO4)2 because Mg(CLO4)2β¦
Correct answer: 50% KOH solution- A. 6.022 x 10^23 /1.0 x 10^-6
- B. 1.0 x 10^-6 x 6.022 x 10^23 /20.2
- C. 1.0 x 10^-6 x 6.022 x 10^23
- D. 1.0 x 10 -6 x 6.022 x 10^23 / 9.65 x 10^-1
Explanation: No. of electron = n x NA 1.0 x 10-16 x 6.02 x 1023
Correct answer: 1.0 x 10^-6 x 6.022 x 10^23- A. 24 dm3
- B. 22.4 dm3
- C. 80 dm3
- D. 40 dm3
Explanation: At standard Temperature and Pressure (STP) the molar volume (Vm) is the volume occupied by one mole of a chemical element or a chemicalβ¦
Correct answer: 22.4 dm3- A. 0.08
- B. 80
- C. 0.80
- D. 8.0
Explanation: Option C is correct.The explanation is given in image.
Correct answer: 0.80- A. 0.25
- B. 0.50
- C. 1.00
- D. 1.50
Explanation: Option B is correct.The number of moles of CO2 which contain 16 g of oxygen is 0.5 moles.
Correct answer: 0.50