Free Moles and Avogadro's Number MCQs with Answers
117 Moles and Avogadro's Number MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The mole connects the microscopic number of particles with measurable mass, using Avogadro's number, 6.022 × 10²³ particles per mole. Questions involve molar mass, conversion between mass, moles and particles, percentage composition, empirical and molecular formulas, and distinguishing atoms, molecules, ions and formula units.
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117 questions · page 5 of 6
- A. 0.1, 0.2
- B. 0.1, 0.3
- C. 0.2, 0.4
- D. 0.2, 0.1
Explanation: d) 0.2 moles of hydrogen ions (H+) and 0.1 mole of sulfate ions (SO4^2-):Using the same calculation as above, we get:Moles of H+ ions ≈…
Correct answer: 0.2, 0.1- A. 8g of oxygen
- B. 16g of oxygen
- C. 32g of oxygen
- D. 24g of oxygen
Explanation: Option D is the right answerSolution number of moles of Al = given mass/molar mass=27/27= 1 moleThe balance equation for such reaction…
Correct answer: 24g of oxygen- A. Mass
- B. Volume
- C. Moles
- D. All of these options are correct
Explanation: If we are given the mass of a substance, we can calculate the mass, volume, and moles of the other substance with the help of a balanced…
Correct answer: All of these options are correct- A. 1
- B. 2
- C. 3
- D. 4
Explanation: Correct option is B. A molecule of water has two bonds so 1 mole of water will contain 2 mole of bonds.
Correct answer: 2- A. Qualitative
- B. Quantitative
- C. Both A & B
- D. Extensive
Explanation: Both qualitative and quantitative analysis were used in the 17th century to study the composition of pure substances.
Correct answer: Quantitative- A. One million
- B. Two million
- C. One billion
- D. Two billion
Explanation: 'Fullstops' contain millions of atoms, substantiating how small atoms are, to an extent where millions can fit in a small dot, placed…
Correct answer: Two million- A. Mass-mass relationship
- B. Mass-mole relationship
- C. Mole-volume relationship
- D. Mass-volume relationship
Explanation: A is incorrect as mass-mass relationship involves converting the mass of a reactant to moles of reactant, then using mole ratios to…
Correct answer: Mass-volume relationship- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: D is correct as Avogadros law states - Equal volume of all ideal gases at equal temperature contain equal number of moles
Correct answer: Option D- A. 6.67 x 10^-14
- B. 1.5 x 10^-14
- C. 6.67 x 10^14
- D. 1.5 x 10^14
Explanation: As we have to distribute 5 rupee coins to 100 people so,100/5 =20 coinsNow multiply these coins by the total population alive in…
Correct answer: 6.67 x 10^-14- A. 4g of O2
- B. 4.5g of H2O
- C. 4g of Cl2
- D. 1 moles of NaCl
Explanation: First, we need to calculate the number of moles of CO2 in 11g of CO2 So, 44g of CO2 is 1 mole, then 11g of CO2 is how many moles?
Correct answer: 4.5g of H2O- A. CH2O
- B. C4H12O2
- C. C2H6O
- D. CH4O
Explanation: Convert g CO2 to g C.Convert g H2O to g H.g O = total g - g C - g Hg C = g CO2 x (C/CO2) = 1.039 x 12.01/44.01 = approx 0.2833g g H = g…
Correct answer: C2H6O- A. An atom of C - 12
- B. 1/12th of a carbon
- C. 1/12th of H
- D. 1 atom of all the elements
Explanation: The atomic mass unit (amu) is a unit of mass used to express the mass of atomic and subatomic particles.
Correct answer: 1/12th of a carbon- A. Mass of an element
- B. Empirical formula mass
- C. Molar mass of an element
- D. Formula mass
Explanation: Since molar mass is constant for a given element, increasing the mass increases the number of moles proportionally.
Correct answer: Mass of an element- A. Overall mass of an isobar
- B. It is a fractional mass.
- C. It is molar mass of Ne
- D. The average atomic mass of Ne
Explanation: The atomic mass of an element like Neon (Ne) is typically expressed as an average atomic mass because neon exists as a mixture of…
Correct answer: The average atomic mass of Ne- A. 4.5 x 10^23
- B. 3.6 x 10^24
- C. 2.7 x 10^24
- D. 9.0 x 10^23
Explanation: In one molecule of aluminum carbonate, there are 3 molecules of carbonate ions, which have 3 oxygen atoms each so there are 9 atoms of…
Correct answer: 2.7 x 10^24- A. 0.643
- B. 0.779
- C. 28.0
- D. 1.28
Explanation: 1 mole: 58.5 g of NaCl x mole: 75 g of NaCl x=1.28
Correct answer: 1.28- A. HN2
- B. NH3
- C. HN3
- D. NH2
Explanation: H N Moles: 0.1/1 4.20/14Divide by the smallest number calculated : 0.1/0.1 0.3/0.1Answer: 1 3HN3
Correct answer: HN3- A. 178
- B. 34g
- C. 51g
- D. 40g
Explanation: 74g of Ca(OH)2 equals 1 mole since the molar mass is 74 g/mol. The dissociation of Ca(OH)2 produces 2 moles of OH ions for every mole of…
Correct answer: 34g- A. Definite proportion
- B. Multiple proportion
- C. Reciprocal proportion
- D. None of above
Explanation: The law of constant composition states that a given chemical compound always contains its component elements in fixed ratio (by mass) and…
Correct answer: Definite proportion- A. 5 x 6.02 x 10^23 atoms
- B. 30 x 6.02 x 10^23
- C. 3x x 6.02 x 10^23
- D. 6 x 6.02 x 10^23
Explanation: The number of atoms in one mole of substance can be calculated byNo. Of atoms = atomicity X Avogadro's no.As a molecule of Ca(OH)2…
Correct answer: 5 x 6.02 x 10^23 atoms