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 44 of 45
- 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. 60%
- B. 58%
- C. 90%
- D. 50%
Explanation: The above question states that 1-bromopropane i.e CH3-CH2-CH2-Br has a molar mass of 123g is being prepared from 10g of 1-propanol i.e…
Correct answer: 58%- A. N2
- B. H2
- C. both (a) & (b)
- D. None of these
Explanation: The balanced chemical equation for the production of ammonia is: N2 + 3H2 → 2NH3.
Correct answer: N2- A. N2
- B. H2
- C. Both a & b
- D. None of them
Explanation: The balanced chemical equation for the formation of ammonia (NH3) is:N2 + 3H2 → 2NH3You start with 28.0 g of N2 and 8.0 g of H2.
Correct answer: N2- A. N2
- B. H2
- C. Ammonia
- D. None of the above
Explanation: The balanced equation is shown below. N2 (g)+ 3H2 (g) → 2NH3 (g) If equal moles of each reactant are used, hydrogen will be the limiting…
Correct answer: H2- A. XeF6, 25.5 g
- B. SiO2, 26 g
- C. XeF6, 52 g
- D. SiO2, 52 g
Explanation: To solve this problem, first calculate the moles of each reactant. For XeF6, with a molar mass of 245.3 g/mol, 122.6 g is equivalent to…
Correct answer: XeF6, 25.5 g- A. Oxygen gas
- B. Liquid ethanol
- C. Both A and B
- D. None of the above
Explanation: The heating reagent in this reaction is oxygen gas. When ethanol and oxygen gas are sparked together, they undergo a combustion reaction…
Correct answer: Oxygen gas- A. Liquid ethanol
- B. Oxygen gas
- C. Both (A) and (B)
- D. None of the stove
Explanation: So, in the reaction between liquid ethanol and oxygen gas, we need to figure out which one is the limiting reagent.
Correct answer: Liquid ethanol- A. H2 is the excess agent
- B. O2 is the limiting agent
- C. H2 is the limiting reagent
- D. The reaction has no limiting reagent
Explanation: Option C is the correct answer. In the reaction 2H2 + O2 --> 2H2O, we start with 5 moles of both hydrogen and oxygen.
Correct answer: H2 is the limiting reagent- 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- A. 17g
- B. 34g
- C. 51g
- D. 40g
Explanation: mole= given mass in gram/molar mass Mole of calcium hydroxide = 74/74 = 1 mole OH- mass in Ca(OH-)2 = (17)2 = 34 OH- ions = 1 x 34 = 34g…
Correct answer: 34g- A. 40L
- B. 30L
- C. 20L
- D. 10L
Explanation: The balanced chemical equation 𝐻2 + 𝐶𝑙2 = 2𝐻𝐶𝑙 shows that each mole of Cl2 produces two moles of HCl.
Correct answer: 20L- A. 4g of hydrogen
- B. 4g of magnesium
- C. 71 g of chlorine
- D. 127 g of iodine
Explanation: Now let's calculate the number of atoms for each substance: a) 4g of hydrogen (H): 4 moles of hydrogen × (6.022 × 1023 atoms/mol) = 2.409…
Correct answer: 71 g of chlorine- A. (5x63.55/76.55)/40x100
- B. 40/5x79.55/63.x100
- C. 5/40x79.55/63.55x100
- D. 25/40x100
Explanation: To find the percentage of copper (Cu) in the sample, we can use the formula:Percentage of Cu = (Mass of Cu / mass of sample) × 100Given…
Correct answer: (5x63.55/76.55)/40x100- A. 1.2L
- B. 22.4L
- C. 30.5L
- D. 44.8L
Explanation: To determine the volume of the gas at STP (Standard temperature pressure), we can use Avogadro's law, which states that equal volumes of…
Correct answer: 22.4L