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 7 of 45
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Option A represents the atomic mass ("A") above and the atomic number ("Z") below.
Correct answer: Option A- A. 4
- B. 2
- C. 8
- D. 16
Explanation: Moles of 'H' atom in given volume of gas: 22.414 dm3 (1 mole) of methane gas contains 4 moles of H-atoms.
Correct answer: 2- A. 64 g
- B. 100 g
- C. 32 g
- D. 71 g
Explanation: Option A is correct.The relative atomic mass of oxygen is 16 amu, which means that one mole of oxygen atoms has a mass of 16 grams.
Correct answer: 64 g- A. 0.0025 mole
- B. 0.25mole
- C. 0.025 mole
- D. 2.5 mole
Explanation: 0.1kg is equal to 100g hence 10g of Calcium present 1mole of Ca => 40g of Ca xmole of Ca => 100g of Ca x= 2.5moles of Ca
Correct answer: 2.5 mole- A. 2 x 6.022 x 10^23 atoms
- B. 2 x 10^23 atoms
- C. 35.5 x 6.022 x 10^23 atoms
- D. 2 x 6.02 x 10^22 atoms
Explanation: Number of atoms = n X NA No. of CI atoms = 2 x 6.02x1023 Hence, option a is correct.
Correct answer: 2 x 6.022 x 10^23 atoms- A. 1g of Ni (s)
- B. 1g of Ca (s)
- C. 1g of N2
- D. 1g of B
Explanation: As the Mr of B(boron) is least hence the number of atoms is greatest in 1g of Boron.
Correct answer: 1g of B- A. Cr
- B. Ca
- C. Mg
- D. Mn
Explanation: M+S-4 MSStoichlometrically, S:MI mole: I mole0.09 mole: 0.09 moleand 0.09 mole of M = 3.6gI mole of M =3640g or Ca.0.09
Correct answer: Ca- A. NO2 and CO2
- B. Na and NH3
- C. CH4 and O2
- D. N2 and CO
Explanation: Two 1g mol molecules having the same weight means that they will have the same molecular mass.
Correct answer: N2 and CO- A. 90 g
- B. 36 g
- C. 18 g
- D. 100 g
Explanation: Molecular mass of water = 16 + 2 = 18mass = mol x Mr = 5 x 18 = 90g
Correct answer: 90 g130. A polymer of empirical formula CH2 has a molar mass of 28000gmol-I. What is its molecular formula?
- A. (CH2)1400
- B. (CH2)2000
- C. (CH2)2800
- D. (CH2)2500
Explanation: The compound must have a molecular formula of 28000. Mr (CH2)2000 = (12+2) x 2000 = 28000 Hence, option B is correct.Another way of…
Correct answer: (CH2)2000- A. 3.6g H2O
- B. 2.8g of CO
- C. 4.8g of C2H5OH
- D. 5.4g of N2O5
Explanation: The largest number of molecules are present in 3.6g of H2O. Mr of H2O= 2x1 + 16 = 18 Mole= Mass/Mr Mole= 3.6/18 = 0.2mol 1mole =…
Correct answer: 3.6g H2O- A. 1.5 x 10^23
- B. 1.34 x 10^22
- C. 3.01 x 10^23
- D. 3.01 x 10^22
Explanation: At STP (Standard Temperature and Pressure), 1 mole of any gas occupies 22.4 dm3.
Correct answer: 1.5 x 10^23- A. 10 moles
- B. 6 moles
- C. 8 moles
- D. 4 moles
Explanation: The balanced equation for the reaction of hydrogen and oxygen is: 2H2 + O2 → 2H2O.This equation tells us that 2 moles of hydrogen react…
Correct answer: 10 moles- A. 23 g
- B. 4.0 g
- C. 40 g
- D. 20 g
Explanation: NaOH : Na.1 mole : 6.02x1023 atoms40g : 6.02x1023 atoms. The mass of NaOH containing 6.02x1023 sodium atoms is 40 grams.The molar mass of…
Correct answer: 40 g- A. 3 moles
- B. 0.27 moles
- C. 0.75 moles
- D. 1.5 mole
Explanation: First, write a balanced chemical equation for the reaction 4Al+ 3O2 ---> 2Al2O3 Calculate the moles in 27g Al (we know that Mr of Al is…
Correct answer: 0.75 moles- A. 6.023 x 10^23
- B. 3.011 x 10^23
- C. 6.023 x 10^21
- D. 6.023 x 10^22
Explanation: Mass of CO2 = 12 Mr of CO2 = 12 + 16 + 16 = 44 Moles of CO2 = mass / mr = 22/44 = 0.5 No.
Correct answer: 3.011 x 10^23- A. 1.008mg
- B. 0.55mg
- C. 1.09 mg
- D. 0.275mg
Explanation: The mass of one mole of electrons is approximately 5.48579909070 × 10-4 grams.
Correct answer: 1.09 mg- A. Which is present in maximum amount
- B. Which produces minimum no. of moles of product
- C. Which produces maximum no. of moles of product
- D. Does not affect the amount of product
Explanation: To summarize, the correct answer is option B) "Which produces the minimum number of moles of product".
Correct answer: Which produces minimum no. of moles of product- A. 0.9 mole
- B. 36 moles
- C. 1.8 moles
- D. 3.6 moles
Explanation: To summarize, the correct answer is option A) 0.9 mole of CO2.If 0.9 moles of O2 react, we need to determine the stoichiometric ratio…
Correct answer: 0.9 mole- A. C2H4Cl
- B. C4H8Cl
- C. C2H4Cl2
- D. C2H3Cl3
Explanation: Empirical formula mass = 49.5 g Molecular mass = 99 g Therefore n = 2 Therefore molecular formula of compound = (CH2Cl)2 The compound is…
Correct answer: C2H4Cl2