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 8 of 45
- A. 2 x 6.02 x 10^-23 atoms
- B. 35.5 x 6.02 x 10 23 atoms
- C. 2 x 10^23 atoms
- D. 2 x 2 x 6.02 x 10^23 atoms
Explanation: Number of molecules = 2 moles × Avogadro's numberNumber of molecules = 2 moles × 6.022 x 1023 molecules/moleNumber of molecules = 1.2044 x…
Correct answer: 2 x 2 x 6.02 x 10^23 atoms- A. 200.
- B. 155.
- C. 400.
- D. 355.
Explanation: For the least possible molecular mass of the compound there must be only 1 sulphur atom in the compound.
Correct answer: 400.- A. 1 gm molecules.
- B. 5 gm molecules.
- C. 2 gm molecules.
- D. 8 gm molecules.
Explanation: 6.0 2 ×10²³ molecules of CO contain 6.023×10²³ molecules of oxygen. 6.02 ×10²³ molecules of CO contain 6.023×10²³ molecules of oxygen.
Correct answer: 5 gm molecules.- A. 1.6 x 10^21
- B. 9.0 x 10^22
- C. 3.6 x 10^23
- D. 4.8 x 10^23
Explanation: Moles of S8=0.125 moles. No. of atoms of S8= (8)(0.125)(6.0x1023) =4..86x1023 .Therefore option D is the correct answer.
Correct answer: 4.8 x 10^23- A. Methanol, Methanoic acid.
- B. Glucose, Benzene.
- C. Methoxy methane, Ethanal.
- D. Ethanoic acid, methanal.
Explanation: The actual whole number ratio of ethanoic acid is 2:4:2 and that of methanal is 1:2:1.
Correct answer: Ethanoic acid, methanal.- A. 14.5.
- B. 14.14.
- C. 14.
- D. 12.6.
Explanation: The atomic mass of Carbon-12 is 12 and of carbon-14 is 14, and it's mentioned that carbon-12 is 70% (i.e 0.7) and carbon-14 is 30%(i.e…
Correct answer: 12.6.- A. CO and H2O
- B. CO2 and H2O2
- C. CO2 and H2O
- D. All of them
Explanation: Option C is correct as the complete combustion produces carbon dioxide and water.
Correct answer: CO2 and H2O- A. 44 g
- B. 88 g
- C. 4.4 g
- D. 8.8 g
Explanation: The balanced equation is: 2CO + O2 → 2CO2 From the balanced equation, we can see that the molar ratio between CO and CO2 is 2:2, meaning…
Correct answer: 8.8 g- A. M2O
- B. M2O3
- C. MO
- D. M3M4
Explanation: O = 40%no = 40/16no = 2.5 M=60%nM = 60/24nM = 2.5 M: O2.5/2.52.5/2.5MO = Empirical formula
Correct answer: MO- A. 3.01 x 10^24
- B. 30.1.1024
- C. 4.06 x 10^24
- D. 3.01 x 10^23
Explanation: Correct option A molecular mass of CaCO3 = (1 x 40) + (1 x 12) + (3 x 16) = 100 mass of CaCO3 given = 10 g no of moles in 10 g of CaCO3…
Correct answer: 3.01 x 10^24- A. Number of atoms
- B. Number of neutrons
- C. Number of protons
- D. Number of electrons
Explanation: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
Correct answer: Number of neutrons- A. Internal structural changes in matter
- B. Composition of matter
- C. Properties of matter
- D. Composition and properties of matter
Explanation: The soul of chemistry is best described by option d. "Composition and properties of matter." Chemistry explores the composition of…
Correct answer: Composition and properties of matter- A. it has 20 mol of hydrogen atoms
- B. it has 30 mol of oxygen atoms
- C. it has 80 mol of atoms
- D. 30 mol of hydrogen atoms
Explanation: As explained hydrogen has 40 mol and oxygen also has 40 mol so the other options are incorrect.
Correct answer: it has 80 mol of atoms- A. they are isotopes
- B. compounds of both with CI2 will be similar in reactivity toward other compounds
- C. both have the same colors
- D. both have the same melting points
Explanation: Isotopes are atoms of the same element (with the same proton number) but can have different numbers of neutrons.
Correct answer: they are isotopes- A. 301.5 a.m.u
- B. 302.5 a.m.u
- C. 303.5 a.m.u
- D. 304.5 a.m.u
Explanation: Dr. Khan has discovered two isotopes of an element with atomic number 119.
Correct answer: 301.5 a.m.u- A. gram
- B. kilogram
- C. microgram
- D. gram/lit
Explanation: Gram, kilogram, microgram are units of mass similar to a.m.u while gram/lit is a unit of concentration therefore gram/lit is not related…
Correct answer: gram/lit- A. two
- B. three
- C. five
- D. one
Explanation: The number of significant figures in a given number is determined by the non-zero digits, any zeros between them, and any zeros to the…
Correct answer: three- A. are always similar
- B. are always different
- C. may be similar or different
- D. ionic compounds don't' have any empirical formula
Explanation: The empirical formula of a compound gives the simplest, most reduced ratio of the elements present in the compound.
Correct answer: are always similar- A. to carry out complete combustion
- B. to reduce the economy of the process
- C. to reduce the time for completion of the reaction
- D. all of the above
Explanation: Complete Combustion: Copper (II) oxide serves as an oxidizing agent. In combustion analysis, the organic compound is burned in the…
Correct answer: to carry out complete combustion- A. 2 g
- B. 20 g
- C. 40 g
- D. 80 g
Explanation: To find the mass of 2 moles of sodium hydroxide (NaOH), you need to know the molar mass of NaOH and then use the formula:Mass=Number of…
Correct answer: 80 g