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 16 of 45
- A. Qualitative
- B. Quantitative
- C. Both A & B
- D. Extensive
Explanation: The quantitative study of composition refers to the measurement of the amount or proportion of elements present in a substance.
Correct answer: Quantitative- A. Percentage
- B. Actual
- C. Theoretical
- D. All of these options are correct
Explanation: Option A is correct since percentage yield shows how much product is obtained compared to the maximum possible mass.
Correct answer: Percentage- A. OH-
- B. CO32-
- C. Cr2O72-
- D. All of these
Explanation: The negative ions having a group of atoms are called polyatomic ions. Examples of polyatomic ions include carbonate (CO3-2), sulfateβ¦
Correct answer: All of these- A. Dots
- B. Atoms
- C. Sub particles
- D. Electrons
Explanation: Option A: This option is not directly related to atomicity. Dots are often used in structural formulas or Lewis dot diagrams to representβ¦
Correct answer: Atoms- A. 1.8 mg
- B. 0.184 mg
- C. 0.55 mg
- D. 0.64 mg
Explanation: The mass of one mole of electrons is approximately 0.55 mg. For electrons, the molar mass is calculated based on their atomic mass.
Correct answer: 0.55 mg- A. Lesser
- B. Moderate
- C. Greater
- D. Equal
Explanation: The greater the number of moles, the greater will be the number of molecules.
Correct answer: Greater- A. Masses of isotopes
- B. Percentages of isotopes
- C. Relative abundances of isotopes
- D. Mass numbers of isotopes
Explanation: Mass spectrometers measure the relative abundances of isotopes of an element.
Correct answer: Relative abundances of isotopes- A. 0.75
- B. 1.50
- C. 0.25
- D. 1.00
Explanation: 32 g of oxygen = 1 mole of O2For 8 frames, the number of moles is 8/32 = 0.25 moles of O21 mole of O2 equals 1 mole of CO2Then, 0.25 molesβ¦
Correct answer: 0.25- A. 40 g
- B. 2.5 g
- C. 5 g
- D. 20 g
Explanation: Sodium hydroxide = NaOH Molar mass of NaOH = 39.99 We know that number of moles = mass/molar mass 0.5 = mass/39.99 Mass =19.99 19.99 g canβ¦
Correct answer: 20 g310. Choose the correct option regarding number or particles associated with one mole of a substance:
- A. 6.03 x 10^23
- B. 6.01 x 10^-19
- C. 6.02 x 10^-23
- D. 6.02 x 10^23
Explanation: One mole of a substance always contains 6.02 x 1023 particles, this is Avogadro's number. (Fact)
Correct answer: 6.02 x 10^23311. The mass of ππππ» needed to prepare 0.2 molal solution in 500π pure water at 4β is:
- A. 0.4π
- B. 4.0π
- C. 1.5π
- D. 1.0π
Explanation: As for 0.2 molal solution 0.2 mole of NaOH is needed to dissolve in 1000 grams of water.
Correct answer: 4.0π- A. C6H12O6
- B. C4H8O2
- C. C5H10O4
- D. C5H10O5
Explanation: The molecular formula is given byMolecular formula = n x empirical formulaWhere n= molecular formula mass/empirical formula massTheβ¦
Correct answer: C5H10O5- A. Theoretical yield
- B. Actual amount
- C. Limiting amount
- D. Stoichiometric amount
Explanation: The amount of the products obtained in a chemical reaction is called the actual yield of that reaction.
Correct answer: Theoretical yield- A. Excess amount
- B. Actual amount
- C. Limiting amount
- D. Stoichiometric amount
Explanation: A stoichiometric quantity is the amount of product or reactant specified by the coefficients in a balanced chemical equation.
Correct answer: Stoichiometric amount- A. Nao
- B. NaO2
- C. Na2O
- D. Na2O2
Explanation: Let's find the empirical formula step-by-step π1οΈβ£ Assume 100 g of the compound β Na = 74.2 g, O = 25.8 g2οΈβ£ Convert to moles: Na = 74.2β¦
Correct answer: Na2O- A. Same number of neutrons
- B. Same mass number
- C. Same physical properties
- D. All of these
Explanation: The correct answer is D) "All of these." Isotopes have different numbers of neutrons, different mass numbers, and while they have similarβ¦
Correct answer: All of these- A. 24 dm3
- B. 22414 cm3
- C. 22.4 dm3
- D. 0.22414 dm3
Explanation: 1 mole of any gas occupies 22.4 dm3 volume at STP.
Correct answer: 22.4 dm3- A. 18.6 g
- B. 36 g
- C. 56 g
- D. 112 g
Explanation: The equivalent weight of any substance is the mass of the substance in grams that combines with or is chemically equivalent to eight gramsβ¦
Correct answer: 18.6 g- A. Chlorine
- B. Hydrogen
- C. Fluorine
- D. Cadmium
Explanation: The number of isotopes of the following elements are:Chlorine 2Hydrogen 3Fluorine 1Cadmium 11
Correct answer: Fluorine- A. 0.25
- B. 1.00
- C. 0.50
- D. 1.50
Explanation: There are 0.5 moles of CO2 which contains 16g of oxygen. This is because one mole of CO2 has a mass of 44g, and oxygen accounts for 32g ofβ¦
Correct answer: 0.50