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 42 of 45
- A. It is her and me they are looking for.
- B. It is she and I they are looking for.
- C. It is me and her they are looking up.
- D. It is land she they are looking for.
Explanation: This option is correct. "She" and "I" are subject pronouns, which are correctly used after the verb "to be."
Correct answer: It is she and I they are looking for.- A. 35 cm³
- B. 40 cm³
- C. 45 cm³
- D. 55 cm³
Explanation: 4NH3 + 3O2→ 6H2O + 2N2 60 cm³ 100 cm³ : Given (22,400 × 4) cm³ of ammonia uses (22,400 × 3) cm³ of O2 1 cm³ of ammonia uses .75 cm³ of O2…
Correct answer: 55 cm³- A. Fractional
- B. Initial
- C. Limiting
- D. Minor
Explanation: The reactant that is in the least amount in the reaction and consumed first is called the limiting reactant.
Correct answer: Limiting- A. Fractional
- B. Initial
- C. Limiting
- D. Minor
Explanation: A limiting reactant is a reactant that is present in the smallest amount in a reaction and therefore limits the amount of product that can…
Correct answer: Limiting- A. 1.5 x 10^23
- B. 1.5 x 10^-23
- C. 0.5 x 10^23
- D. 2.4 x 10^24
Explanation: d) 2.4 x 10^24:This option is the correct answer. The Avogadro's constant is approximately 6.0 x 10^23 mol^-1, which means there are 6.0 x…
Correct answer: 2.4 x 10^24- A. 4
- B. 5
- C. 6
- D. 8
Explanation: 1 molecule of NH4NO3 = 80 amuAs 2 times 80 is 160, therefore by balanced chemical equation, 160 amu of NH4 are present in two molecules.80…
Correct answer: 4- A. C5H10 and C6H12
- B. C2H2 and C6H6
- C. C4H8 and C2H4
- D. All have the ame empirical formula
Explanation: The explanation for this question will be added soon.
Correct answer: All have the ame empirical formula828. The amount (in liters) of oxygen at STP that is required for the combustion of 4g of ethylene is:
- A. 96 liters
- B. 9.6 liters
- C. 44.8 liters
- D. 7.2 liters
Explanation: The balanced equation for this reaction will be C2H4 + 3O2 → 2CO2 + 2H2O Moles of ethylene given: moles= mass/Mr = 4/28 =1/7 moles Molar…
Correct answer: 9.6 liters- A. 1 dm3 of molecule
- B. Mass of one molecule
- C. 1 g of molecule
- D. 1 g atom
- E. 1 mole
Explanation: 1 mole is a unit of measurement that is used to count the number of atoms, molecules, or ions in a substance.
Correct answer: 1 mole- A. 5 mol
- B. 16 mol
- C. 0.5 mol
- D. 2 mol
Explanation: 1 mol of CO2 contains = 32 g O2=1 6 g O2 will be present in = 16/32 = 0.5 mol
Correct answer: 0.5 mol831. Stoichiometry is:
- A. Relationship between quantities of substances in a chemical reaction
- B. Relationship between concentration of substances
- C. Relationship between amount of substances in a chemical equation
- D. All of the above options are correct
Explanation: The relationship between the relative quantities of substances taking part in a reaction or forming a compound is called stoichiometry.
Correct answer: Relationship between quantities of substances in a chemical reaction- A. Molecular formula = empirical formula/n
- B. Molecular formula = n(empirical formula)
- C. Molecular formula = 2n(empirical formula)
- D. Empirical formula = n (Molecular formula)
Explanation: Empirical formulas show the simplest whole-number ratio of atoms in a compound, molecular formulas show the number of each type of atom in…
Correct answer: Molecular formula = n(empirical formula)- A. Mass
- B. Number of atoms
- C. Numbor ol electrons
- D. Number of molecules
Explanation: As the number of atoms is not equal the number of electrons and mass also not equal.
Correct answer: Number of molecules- A. Finding number of gram atoms of each element
- B. Percentage compostion of each element
- C. Atomic: ratio of each element
- D. Multiplication of atomic ratio with whole number
Explanation: Finding the percentage composition of each element is the first step involved in the determination of Empirical Formula ol chemical…
Correct answer: Percentage compostion of each element- A. 0.25
- B. 0.5
- C. 1.00
- D. 1.50
Explanation: One mole of CO2 has a mass of 44 g and 32 g of O2. So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.
Correct answer: 0.5- A. 30.45% Carbon & 69.54% Oxygen
- B. 24.22% Carbon & 75.78% Oxygen
- C. 27 .37% carbon & 72.72% Oxygen
- D. 41.68% Carbon & 58.12% Oxygen
Explanation: The atomic weight of carbon is 12 grams and that of oxygen is 16 grams.
Correct answer: 27 .37% carbon & 72.72% Oxygen- A. 2.5 moles
- B. 2 moles
- C. 5 moles
- D. 7.5 moles
Explanation: The ratio of N2:NH3 is 1:2 so if 2.5 moles of N2 are used 5 moles of NH3 should be formed provided that hydrogen is in excess HTtT
Correct answer: 5 moles- A. 32g
- B. 24g
- C. 16g
- D. 8g
Explanation: Explanation for this question will be added soon.
Correct answer: 8g- A. 6.22 x 10^23 atoms of U-235
- B. 6.22 x 10^23 atoms of U-238
- C. 6.22 x 10^23 atoms of U-234
- D. All of these options are correct
Explanation: There are three naturally occurring isotopes of uranium: uranium-238, the heaviest and most abundant, uranium-235 and uranium-234.
Correct answer: 6.22 x 10^23 atoms of U-238- A. 1.8mg
- B. 0.184mg
- C. 0.55mg
- D. 0.64mg
Explanation: We know that:Mass of an electron = 9.1 ×10-³¹Avogadro's constant = 6.02 ×10²³Mass of one mole Electron: = 9.1 × 10-³¹ × 6.02 × 10²³ = 5.48…
Correct answer: 0.55mg