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 40 of 45
- A. A limiting reactant is consumed at the end of reaction
- B. Actual yield is always greater than theoretical yield
- C. Stochiometric calculation can be only done if no side reaction happens
- D. The empirical formula and molecular formula of some of compounds are same
Explanation: Actual yield is always less than theoretical yield
Correct answer: Actual yield is always greater than theoretical yield- A. 1.008x1.661 x 10^-23 kg
- B. 1.008x1.661 x 10^-27kg
- C. 1.00
- D. 1.661 x 10^-27kg
Explanation: Explanation for this question will be added soon!
Correct answer: 1.008x1.661 x 10^-27kg- A. 1 mole
- B. 2 moles
- C. 0.5 moles
- D. 0.25 moles
Explanation: Explanation for this question will be added soon!
Correct answer: 0.5 moles- A. 100°C, 1 atm
- B. 298 K, I atm
- C. 273 K 760 mm Hg
- D. 0°C, 760 cm Hg
Explanation: Explanation for this question will be added soon!
Correct answer: 273 K 760 mm Hg- A. 2.24dm3
- B. 22.4dm3
- C. 11.02dm3
- D. 1.24dm3
Explanation: According to Avogadro's Law and the molar mass of oxygen (O₂), which is approximately 32 g/mol, 1 mole of oxygen gas occupies 22.4 dm³ at…
Correct answer: 11.02dm3- A. All the reactants are completely converted into products
- B. Reversible reaction occurs
- C. In calculations, law of conservation of mass and law of definite proportions are obeyed
- D. Side reaction occurs
Explanation: Correct answer is D. A side reaction, also known as a secondary reaction, is a chemical reaction that occurs simultaneously with the…
Correct answer: Side reaction occurs- A. 40 g
- B. 30 g
- C. 50 g
Explanation: Molar mass of Na= 23g/mo. Moles of Na= 23/23= 1 mole Sodium has one valence electron. Calcium has one valence electron per mole of sodium.
Correct answer: 40 g- A. it occupies 2.24 litre at STP
- B. it corresponds to same mole of CO and N2
- C. it corresponds to 0.5 mol f CO
- D. it corresponds to 3.01 x 10^23 molecules of CO
Explanation: Explanation for this question will be added soon!
Correct answer: it occupies 2.24 litre at STP- A. 6.02 x 10^23 atoms of C
- B. 6.02 x 10^23 atoms of O
- C. 8.1 x 10^23 atoms of CO2
- D. Option D
Explanation: Explanation for this question will be added soon!
Correct answer: 6.02 x 10^23 atoms of C- A. 1 mole means 6.023 x 10^23 particles
- B. Molar mass is mass of 1 molecule
- C. Mole is mass of 1 mole of substance
- D. Molar mass is molecular mass expressed in grams
Explanation: Explanation for this question will be added soon!
Correct answer: Molar mass is mass of 1 molecule- A. Mass of compound/Mass of element -x100
- B. Mass of molecule/Mass of compound x100
- C. Mass of element/Mass of molecule x100
- D. Mass of element/Mass of compound x1000
Explanation: An explanation for this question has been added!
Correct answer: Mass of element/Mass of molecule x100- A. 1.66×10-²⁷
- B. 2.45×10-³¹
- C. 2.77×p10³⁴
- D. 9.34×10-²⁵
Explanation: Fact, learn it (it is 1/12th the mass of Carbon-12).
Correct answer: 1.66×10-²⁷- A. why do isotopes have different physical properties?
- B. Isotopes have same atomic number
- C. Isotopes of an element have different mass number
- D. Isotopes of an element have different atomic number
Explanation: The variation of atomic mass in isotopes can influence its physical properties like Density, Melting and boiling point and stability.
Correct answer: Isotopes of an element have different mass number- A. 64g
- B. 32g
- C. 100g
- D. 71g
Explanation: Mole= Mass/ relative atomic mass. Mass = Mole x Relative atomic mass Mass= 2 x 32(Because oxygen gas written so it means O2, O is 16 so O2…
Correct answer: 64g- A. Number of ions
- B. Empirical formula of organic compounds
- C. Structure formula
- D. Isotope of an element
Explanation: Combustion analysis provides valuable information for determining the empirical formula or molecular formula of an organic compound by…
Correct answer: Empirical formula of organic compounds- A. chemical change
- B. Physical change
- C. Neither chemical nor physical change
- D. .
Explanation: 2 KOH + CO₂ → K₂CO₃ + H₂O It is a chemical change because it involves breaking and forming new chemical bonds.
Correct answer: chemical change- A. C3H404
- B. C2H2O
- C. C2H2O4
- D. C2HO2
Explanation: C : H : O 34.6/12 :3.5/1 : 61.5/16 3 : 4 : 4 => E:F= C3H4O4 =>E.F.Mass= (3x12)+(1x4)+(4x16) = 104 => n= Molecular Mass/ E.F.Mass = 104/104…
Correct answer: C3H404- A. 80 moles of atoms
- B. 40 moles of hydrogen atom
- C. 30 moles of electrons
- D. 30 moles of oxygen atoms
Explanation: 2H + O --> H2O H : H2O 2 : 1 X : 20 X=40 moles of hydrogen atom. (Correct)
Correct answer: 40 moles of hydrogen atom- A. 2.24 dm3
- B. 112cm3
- C. 22.4dm3
- D. 1.12dm3
Explanation: Moles = Mass / Mr = 4.4 / 48 = 0.1 ● Volume= Mole x 22.4 dm3(in STP) = 0.1 x 22.4 = 2.24 dm3
Correct answer: 2.24 dm3- A. 4.3×10-³
- B. 4.01×10-²
- C. 4.03×10-¹
- D. 4.3×10-²
Explanation: Ar of Na= 23g/mol Mole=Mass/Mr Mole= 0.1/23 Mole= 4.3x10^-3
Correct answer: 4.3×10-³