All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 619 of 686
- A. Reaction Mixture.
- B. Reactants.
- C. Equilibrium Mixture.
- D. Products.
Explanation: Le Chatelier's principle is a fundamental principle of chemical equilibrium that predicts the effect of a change in conditions on a system…
Correct answer: Equilibrium Mixture.- A. Reaction Mixture
- B. Reactants
- C. Equilibrium Mixture
- D. Products
Explanation: Option C is correct since Le Chatelier's principle is an observation about the chemical equilibria of reactions.
Correct answer: Equilibrium Mixture12363. With different number of moles of reactants and product, what happens to the volume of the system?
- A. It remains unchanged
- B. It changes
- C. It decreases
- D. It increases
Explanation: According to the ideal gas law, PV = nRT, the volume of a gas is directly proportional to the number of moles of gas present (n), assuming…
Correct answer: It changes- A. Liquid state
- B. Solid State
- C. Plasma state
- D. Gaseous state
Explanation: A change in pressure primarily affects substances in the gaseous state.
Correct answer: Gaseous state- A. 35 cm³
- B. 40 cm³
- C. 45 cm³
- D. 55 cm³
Explanation: 4NH3 + 3O2→ 6H2O + 2N2 60 cm³ 100 cm³ : Given (22,400 × 4) cm³ of ammonia uses (22,400 × 3) cm³ of O2 1 cm³ of ammonia uses .75 cm³ of O2…
Correct answer: 55 cm³- A. Fractional
- B. Initial
- C. Limiting
- D. Minor
Explanation: The reactant that is in the least amount in the reaction and consumed first is called the limiting reactant.
Correct answer: Limiting- A. Fractional
- B. Initial
- C. Limiting
- D. Minor
Explanation: A limiting reactant is a reactant that is present in the smallest amount in a reaction and therefore limits the amount of product that can…
Correct answer: Limiting- A. 1.5 x 10^23
- B. 1.5 x 10^-23
- C. 0.5 x 10^23
- D. 2.4 x 10^24
Explanation: d) 2.4 x 10^24:This option is the correct answer. The Avogadro's constant is approximately 6.0 x 10^23 mol^-1, which means there are 6.0 x…
Correct answer: 2.4 x 10^24- A. 4
- B. 5
- C. 6
- D. 8
Explanation: 1 molecule of NH4NO3 = 80 amuAs 2 times 80 is 160, therefore by balanced chemical equation, 160 amu of NH4 are present in two molecules.80…
Correct answer: 4- A. C5H10 and C6H12
- B. C2H2 and C6H6
- C. C4H8 and C2H4
- D. All have the ame empirical formula
Explanation: The explanation for this question will be added soon.
Correct answer: All have the ame empirical formula12371. The amount (in liters) of oxygen at STP that is required for the combustion of 4g of ethylene is:
- A. 96 liters
- B. 9.6 liters
- C. 44.8 liters
- D. 7.2 liters
Explanation: The balanced equation for this reaction will be C2H4 + 3O2 → 2CO2 + 2H2O Moles of ethylene given: moles= mass/Mr = 4/28 =1/7 moles Molar…
Correct answer: 9.6 liters- A. 1 dm3 of molecule
- B. Mass of one molecule
- C. 1 g of molecule
- D. 1 g atom
- E. 1 mole
Explanation: 1 mole is a unit of measurement that is used to count the number of atoms, molecules, or ions in a substance.
Correct answer: 1 mole- A. 5 mol
- B. 16 mol
- C. 0.5 mol
- D. 2 mol
Explanation: 1 mol of CO2 contains = 32 g O2=1 6 g O2 will be present in = 16/32 = 0.5 mol
Correct answer: 0.5 mol12374. Stoichiometry is:
- A. Relationship between quantities of substances in a chemical reaction
- B. Relationship between concentration of substances
- C. Relationship between amount of substances in a chemical equation
- D. All of the above options are correct
Explanation: The relationship between the relative quantities of substances taking part in a reaction or forming a compound is called stoichiometry.
Correct answer: Relationship between quantities of substances in a chemical reaction- A. Molecular formula = empirical formula/n
- B. Molecular formula = n(empirical formula)
- C. Molecular formula = 2n(empirical formula)
- D. Empirical formula = n (Molecular formula)
Explanation: Empirical formulas show the simplest whole-number ratio of atoms in a compound, molecular formulas show the number of each type of atom in…
Correct answer: Molecular formula = n(empirical formula)- A. Mass
- B. Number of atoms
- C. Numbor ol electrons
- D. Number of molecules
Explanation: As the number of atoms is not equal the number of electrons and mass also not equal.
Correct answer: Number of molecules- A. Finding number of gram atoms of each element
- B. Percentage compostion of each element
- C. Atomic: ratio of each element
- D. Multiplication of atomic ratio with whole number
Explanation: Finding the percentage composition of each element is the first step involved in the determination of Empirical Formula ol chemical…
Correct answer: Percentage compostion of each element- A. 0.25
- B. 0.5
- C. 1.00
- D. 1.50
Explanation: One mole of CO2 has a mass of 44 g and 32 g of O2. So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.
Correct answer: 0.5- A. 30.45% Carbon & 69.54% Oxygen
- B. 24.22% Carbon & 75.78% Oxygen
- C. 27 .37% carbon & 72.72% Oxygen
- D. 41.68% Carbon & 58.12% Oxygen
Explanation: The atomic weight of carbon is 12 grams and that of oxygen is 16 grams.
Correct answer: 27 .37% carbon & 72.72% Oxygen12380. From the equation (N2 + 3H2 ↔ 2NH3), how many moles of NH3 are produced from 2.5 moles of N2?
- A. 2.5 moles
- B. 2 moles
- C. 5 moles
- D. 7.5 moles
Explanation: The ratio of N2:NH3 is 1:2 so if 2.5 moles of N2 are used 5 moles of NH3 should be formed provided that hydrogen is in excess HTtT
Correct answer: 5 moles