Basic Concept MCQs with Answers
How many unstable radioactive isotopes have been produced through artificial disintegration?
The total types of fundamental nuclear sub-atomic particles present in an atom are:
More than 100
3
2
Equal to 100
Chemically similar
Chemically dissimilar
Physically similar
Both ‘A’ and ‘B’
Molecular ions are formed by passing:
High-energy electron beam
α-particle
X-rays
All of the above
Which one is true about isotopes?
Same number of neutrons
Same mass number
Same physical properties
Same chemical properties
The number of moles present in 0.6 grams of silicon (Atomic mass: Si = 28, O = 16) is:
0.01 mole
0.044 mole
0.064 mole
0.054 mole
Volume occupied by 4.4g of CO₂ at STP is:
2.24 dm³
22.4 dm³
2.2 cm³
1.12 dm³
What is the molar volume of a gas at STP?
24 dm³
80 dm³
22.4 dm³
40 dm³
The number of H⁺ ions when 0.1 moles of sulfuric acid is completely ionized in water:
4 × 6.022 × 10²³
2 × 6.022 × 10²³
1 × 6.022 × 10²³
2 × 6.022 × 10²²
When 0.5 moles of Al₂(SO₄)₃ are dissolved in water, the total number of particles produced is:
12 × 10²³
1.5 × 10²⁴
30 × 10²³
2.5 × 10²³
Which of the following contains 1 mole of the stated particles?
Chlorine molecules in 35.5 g of chlorine gas
Hydrogen ions in 1 dm³ of 1 mol dm⁻³ aqueous sulfuric acid
Electrons in 1 g of hydrogen gas
Oxygen atoms in 22.4 dm³ of oxygen gas at STP
The correct representation atomic number is:
How many electrons must be removed to ionize 1.0 × 10-6 Ne atoms to Ne⁺ ions in a neon advertising tube?
(6.022 x 10 23)/(1.0 x 10 -6)
(6.022 x 10 23)x(1.0 x 10 -6)
(6.022 x 10 23)x(1.0 x 10 -6)/20.2
(6.022 x 10 23)x(1.0 x 10 -6)/(9.65x10 -1)
The number of moles of CO₂ which contain 16g of oxygen:
The mass of one molecule of O₂ is:
6.02 × 10²³ g / 32
32 / 6.02 × 10²³ g
0.32 g
32 g
The amount of oxygen in grams which contains 1.5× 10²² molecules:
The number of electrons in half a mole of Na⁺ ions is
3 × 10 -21 moles of an amino acid having a molecular mass of 200 g/mol would have:
200 molecules
300 molecules
1800 molecules
36,000 molecules
The relative atomic mass of oxygen is 16 amu. What is the mass of 2 moles of oxygen?
Which of the following has the maximum mass?
25g of iodine
25g mole of water
25g atom of oxygen
25g of nitrogen gas
The mass of one mole of chlorine gas is:
Which of the following statements is not true for a mole?
It is counting unit.
It is the gram atomic or gram formula mass of a substance.
It contains 6.022 × 10²³ particles.
It contains a different number of particles for different substances.
In combustion analysis, which one is used for absorbing carbon dioxide (CO₂)?
50 % KOH solution
Silica Gel
100 % Ca(OH)₂ solution
10 % Mg(OH)₂ solution
The absorption of CO₂ in KOH solution during combustion analysis is:
A chemical change
A physical change
Neither a chemical nor a physical change
Both a chemical and a physical change
Which of the following compounds has the highest percentage of oxygen by weight?
Which of the following compounds have a empirical formula but no molecular formula?
The sole products of combustion analysis are:
CO₂ and H₂O
Na₂O and CO₂
Na₂CO₃ and H₂O
K₂CO₃ and H₂O
An acid with molecular mass 104 contains 34.6% C, 3.85% H, and the rest is O. The molecular formula of the acid is:
6Na + Fe₂O₃ → 3Na₂O + 2Fe
If you are provided with 230g Na and 320g Fe₂O₃, then the limiting reactant is:
Mg reacts with HCl as per the following reaction:
Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g)
Given that Mg = 21g and HCl = 21g, the excess reactant is:
Mg
HCl
Both are in stoichiometric amounts
None of these
What volume of oxygen is required for the complete combustion of 5 cm³ of C₂H₂?
2 cm³
5 cm³
12.5 cm³
13.5 cm³
11.207 dm³ of methane at STP contains how many moles of hydrogen atoms?
How much Al is required to form alumina with 12g of oxygen?
The actual yield is always less than the theoretical yield due to:
Side reactions
Reversible nature of the reaction
Mechanical loss
All of these
Indicate the incorrect statement from the following:
A limiting reactant is consumed at the end of the reaction.
Actual yield is always greater than theoretical yield.
Stoichiometric calculations can only be done if no side reaction happens.
The empirical formula and molecular formula of some compounds are the same.
The efficiency of a chemical reaction can be checked by knowing the amount of:
The limiting reactant
The excess reagent
The product formed
The substance left unused
When one mole of each of the following is completely burnt in oxygen, which will give the largest mass of CO₂?
If we know the mass of one substance, we can calculate the volume of another substance and vice versa with the help of a chemical equation. This is called:
Mass-mass relationship
Mass-volume relationship
Mass-mole relationship
Mole-volume relationship
With the help of the given spectral data, calculate the mass of Neon and choose the best option.
(Percentage of isotopes: ²⁰Ne = 90.92%, ²¹Ne = 0.26%, ²²Ne = 8.82%)
22.18 amu
20.18 amu
21.18 amu
22.20 amu
How many chlorine atoms are in 2 moles of Cl?
2 × 6.022 × 10²³ atoms
2 × 10³ atoms
35.5 × 6.022 × 10²³ atoms
2 × 6.022 × 10²³ atoms
If we know the mass of one substance, we can calculate the volume of another substance and vice versa with the help of a chemical equation. This is called: (MDCAT 2010)
Mass-mass relationship
Mass-volume relationship
Mass-mole relationship
Mole-volume relationship
One mole of any gas at STP occupies a volume of: (MDCAT 2010)
22.414 dm³
23.414 dm³
22.414 cm³
20.414 dm³
How many chlorine atoms are in 2 moles of Cl? (MDCAT 2011)
2 × 6.022 × 10²³ atoms
35.5 × 6.022 × 10²³ atoms
20 atoms
2 × 6.02 × 10²³ atoms
An organic compound has an empirical formula of C₃H₃O. If the molar mass of the compound is 110.15 g/mol, what is its molecular formula? (MDCAT 2012)
(Atomic masses: C = 12, H = 1.008, O = 16)
When 8 grams (4 moles) of H₂ react with 2 moles of O₂, how many moles of water will be formed? (MDCAT 2012)
Hydrogen burns in chlorine to produce hydrogen chloride. The ratio of masses of reactants in the chemical reaction H₂ + Cl₂ → 2HCl is: (MDCAT 2013)
A polymer with the simplest formula CH₂ has a molar mass of 28,000 g/mol. Its molecular formula will be: (MDCAT 2014)
100 times that of its empirical formula
500 times that of its empirical formula
200 times that of its empirical formula
2000 times that of its empirical formula
The number of molecules in 9g of ice (H₂O) is: (MDCAT 2014)
6.02 × 10²³
6.02 × 10²²
3.01 × 10²³
3.01 × 10²²
How many moles of sodium are present in 0.1g of sodium? (MDCAT 2015)
4.3 × 10⁻³
4.01 × 10⁻²
4.03 × 10⁻³
4.3 × 10⁻²
10.0 grams of glucose are dissolved in water to make 100 cm³ of solution. Its molarity is: (MDCAT 2015)
An organic sample consisting of carbon, hydrogen, and oxygen was subjected to combustion analysis. 0.5439g of this compound gave 1.039g CO₂ and 0.6369g H₂O. The empirical formula of this compound is: (MDCAT 2016)
The number of moles of CO₂ that contain 8.0g of oxygen is: (MDCAT 2016)
A researcher prepared a sample of 1-bromopropane from 10g of 1-propanol. After purification, he obtained 12g of product. What is the percentage yield?(MDCAT 2017)
Which of the following has the same number of molecules as present in 11g of CO₂? (MDCAT 2017)
4g of O₂
4g of O
4.5g of H₂O
1/4 moles of NaCl
Choose the correct option regarding the number of particles associated with one mole of a substance. (MDCAT 2017)
6.03 × 10²³
6.03 × 10⁻²³
6.01 × 10⁻¹⁹
6.02 × 10²³
Determine the number of moles of O in 10.6g of NaCO₂. (MDCAT 2017)
0.4 moles
0.2 moles
0.3 moles
None of these
Calculate the grams of H₂O formed when 8g of CH₄ burns in excess oxygen. (MDCAT 2017)
21 grams
18 grams
19 grams
15 grams
While finding the relative atomic mass, which of the following standards is used to compare the atomic mass of chlorine (35.5 amu)? (MDCAT 2018)
Neon-20
Nucleon number
Carbon-13
Carbon-12
The formula which shows the simplest whole number ratio of the atoms of different elements in a compound is called: (MDCAT 2018)
Ionic formula
Empirical formula
Structural formula
Molecular formula
3.0 moles of calcium will contain how many grams of calcium? (MDCAT 2018)
The average atomic mass of Boron is 10.8. It has two isotopes of masses 10 and 11 respectively. What is the percentage of the isotope with the mass of 10? (MDCAT 2019)
Which two elements are isotopes? (MDCAT 2019)
¹²X₆ and ¹⁴X₆
¹⁶X₈ and ¹⁶X₇
²³X₁₁ and ²³X₁₂
³⁵X₁₇ and ⁴⁰X₁₈
The best standard for the calculation of relative atomic mass is: (NUMS 2019)
H-1.008
Carbon-12
Carbon-13
Oxygen-16
A piece of diamond embedded in a gold ring weighs 6.0 grams. How many moles of carbon does it contain? (SET 2019)
6.0 moles
0.5 moles
1.0 moles
1.5 moles
Iron is manufactured industrially in a blast furnace using hematite (an ore of iron) and carbon monoxide as a reducing agent.
Fe₂O₃ + 3CO → 2Fe + 3CO₂
Calculate the mass of iron ore used to manufacture 56g of iron with excess carbon monoxide. Assume the process gives 100% yield. (SET 2019)
How many moles of calcium carbonate are present in 1.75 kg of calcium carbonate? (MDCAT 2019)
(Ar of Ca = 40, Ar of C = 12, Ar of O = 16)
0.0175 mol
55 mol
17.5 mol
3 mol
According to the law of definite proportions, what is the mass ratio of hydrogen and oxygen in water? (SET 2019)
Hydrogen is 11.11% and oxygen is 88.89%
Hydrogen is 10.11% and oxygen is 89.89%
Hydrogen is 20% and oxygen is 80%
Hydrogen is 30% and oxygen is 70%
Given the reaction:
2XeF₆+SiO₂→3XeOF₄+SiF₄
If 122.6g of XeF₆ reacts with 60g of SiO₂ to form products, identify the limiting reagent and the amount of SiF₄ formed. (XeF₆ = 245.3 amu, SiO₂ = 60 amu, SiF₄ = 104 amu) (ETEA 2016)
XeF₆, 26g
SiO₂, 26g
XeF₆, 52g
SiO₂, 52g
How many oxygen atoms are present in 278g of hydrated ferrous sulfate (FeSO₄·7H₂O = 278amu)? (ETEA 2016)
6.023 × 10²³
6.525 × 10²⁴
2.408 × 10²³
6.023 × 10²²
The water formed in combustion analysis is usually absorbed by: (ETEA 2016)
Mg(NO₃)₂
Mg(ClO₄)₂
Mg(OH)₂
Mg(ClO₂)₂
Which of the following contains more atoms? (ETEA 2019)
7 grams of Mg
8 grams of Na
9 grams of Al
All contain the same number of atoms
Which compound has the highest percentage of nitrogen? (ETEA 2019)
A mixture of 10 cm³ of oxygen and 50 cm³ of hydrogen is sparged continuously. What is the maximum theoretical decrease in volume? (ETEA 2019)
The number of moles of water in 1 kg of ice is: (MDCAT 2019)
50 moles
1000 moles
55.5 moles
100 moles
During stoichiometric calculations, which of the following laws must be followed? (MDCAT 2019)
Law of Conservation of Mass
Law of Conservation of Energy
Avogadro’s Law
Dalton’s Law
The efficiency of a chemical reaction can be expressed as: (NMDCAT 2020)
Theoretical yield
Actual yield
Percentage yield
Maximum yield
In a vessel, 10g of N₂, 10g of H₂, and 10g of O₂ are present. Which one will have the least number of atoms? (NMDCAT 2020)
The empirical formula of glucose (C₆H₁₂O₆) is: (NMDCAT 2020)
Other Chemistry Topics MCQs
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