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 29 of 45
- A. 105 g
- B. 120 g
- C. 80 g
- D. 100 g
Explanation: Moles of Calcium = 3Molar mass of Calcium (Ca) = 40Mass of Calcium in grams = ?Moles = Mass/Molar massMass = Moles × Molar massMass = 3 x…
Correct answer: 120 g- A. 147
- B. 294
- C. 588
- D. 266
Explanation: To find the molecular weight of aspartame, we need to use the information given about the weight percentage of nitrogen and the number of…
Correct answer: 294- A. 6 times
- B. 4 times slower
- C. One fourth times slower
- D. One eighth
Explanation: The rate of diffusion of a gas is inversely proportional to the square root of its molar mass.
Correct answer: 4 times slower- A. 1.5 g
- B. 1 g
- C. 2 g
- D. 3 g
Explanation: H2O2 decomposes into O2 and H2O by the following reaction: 22.4 dm3 of O2 = 1 mole of O2 1 dm3 of O2 = 1/22.4 moles of O2 According to the…
Correct answer: 3 g- A. 2.24 dm³
- B. 24.4 dm³
- C. 2.44 dm³
- D. 22.4 dm³
Explanation: Under Standard Temperature and Pressure (STP), one mole of an ideal gas occupies 22.4 dm3.Under room conditions/ Normal Temperature and…
Correct answer: 22.4 dm³- A. 11.2
- B. 10.2
- C. 10
- D. 10.8
Explanation: Considering that B-11 is more abundant (approx 80%), we can predict the average atomic weight to be nearer to 11 than 10 but still between…
Correct answer: 10.8- A. Mass of reactants
- B. Moles from a balanced equation
- C. Mass of limiting reactants
- D. Mass of product
Explanation: Theoretical yield is the maximum amount of product that can be formed in a chemical reaction.
Correct answer: Mass of limiting reactants- A. 4.3 x 10^-3
- B. 4.03 x 10^-1
- C. 4.01 x 10^-2
- D. 4.3 x 10^-2
Explanation: To calculate the number of moles of sodium present in 0.1g of sodium, we need to use the molar mass of sodium (Na), which is approximately…
Correct answer: 4.3 x 10^-3- A. 65%
- B. 35%
- C. 20%
- D. 58%
Explanation: Mass of N is 14, in NH3NO3 there are two Nitrogens hence the mass of N is 28g.Mass of NH3NO3 = 14+(1x3)+14+(16x3)=79Percentage of N =…
Correct answer: 35%- A. Mole fraction of CH3OH is highest among all components
- B. Mole fraction of C2H5OH and H2O is the same
- C. Mole fraction of CH3OH and C2H5OH is same
- D. Mole fraction of H2O is the lowest among all
Explanation: No. of moles of CH3OH = 16/32 = 0.5No. of moles of C2H5OH= 92/46 =2No. of moles of H2O = 36/18 =2Formula to calculate mole fraction,no.
Correct answer: Mole fraction of C2H5OH and H2O is the same- A. C6H6O2
- B. C3H3O
- C. C9H9O3
- D. C6H6O3
Explanation: The empirical formula mass can be calculated as follows:Empirical formula mass = (3 x atomic mass of C) + (3 x atomic mass of H) + (1 x…
Correct answer: C6H6O2- A. 60.2 x 10^23
- B. 6.02 x 10^22
- C. 6.02 x 10^25
- D. 6.02 x 10^23
Explanation: This is Avogrado's number of molecules, 6.02×1023
Correct answer: 6.02 x 10^23- A. 2 × 6.02 x 10^-23 molecules
- B. 35.5 × 6.02 x 10^23 molecules
- C. 2 x 10^23 molecules
- D. 2 × 6.02 x 10^23 molecules
Explanation: 1 mole of any molecule has 6.02x 1023 molecules (avogadro's constant), so 2 moles of chlorine would have 2 x 6.02 x 1023 molecules.
Correct answer: 2 × 6.02 x 10^23 molecules- A. 6.02 x 10^24
- B. 6.02 x 10^23
- C. 3.01 x 10^24
- D. 3.01 x 10^23
Explanation: Water has a mass of 18g (16+2). So, 9g of ice(H2O) means 0.5 mol. 1 mol has a 6.02x1023 number of molecules, so 0.5 mol will have a…
Correct answer: 3.01 x 10^23- A. 1:35.5
- B. 2:35.5
- C. 1:71
- D. 2:70
Explanation: Mass of 1 mole of H2 = 2x1= 2gMass of 1 mole of Cl2 = 2x35.5 = 71g2 : 711 : 35.5
Correct answer: 1:35.5- A. 20.18
- B. 20.28
- C. 20.10
- D. 20.22
Explanation: Relative atomic mass = Sum of product of isotopic masses and relative abundances/100Relative atomic mass = [(20 × 90.92) + (21 × 0.26) +…
Correct answer: 20.18- A. High temperature and low pressure
- B. High temperature and high pressure
- C. Low temperature and low pressure
- D. Low temperature and high pressure
Explanation: Exothermic reaction is a reaction in which heat is given out. For exothermic reaction, by increasing temperature reaction move backwards…
Correct answer: Low temperature and high pressure- A. 7 gram Mg
- B. 8 gram Na
- C. 9 gram Al
- D. All same
Explanation: As we know, to calculate the number of atoms, [Mass / Molar Mass] x [6.022 x 1023] Hence, Na has the most atoms by putting the values.
Correct answer: 8 gram Na- A. NO
- B. NO2
- C. N2O
- D. N2O5
Explanation: N2O contains the highest percentage of nitrogen i.e, 28/44 × 100 = 63.6 %
Correct answer: N2O- A. 10cm3
- B. 15cm3
- C. 20cm3
- D. 30cm3
Explanation: We'll begin by writing the balanced equation for the reaction. This is given below: O2 + 2H2 -> 2H2O From the balanced equation above, we…
Correct answer: 30cm3