MDCAT Fundamental Concepts of Chemistry Test Online MCQs

MDCAT Fundamental Concepts of Chemistry Online Test

Prepare for MDCAT Chemistry with this online MCQ test on Fundamental Concepts of Chemistry. This quiz covers key basics such as atomic mass, moles, empirical and molecular formulas, and chemical calculations, aligned with the MDCAT 2025 syllabus to build a strong foundation for the subject.

MDCAT 2025 Basic Concepts Online Test

MDCAT Chemistry Basic Concepts Test Question with Answer

Please wait...

 0%

Page 1 of 3

1. Which one of the following is ambiguous?

A mole of electrons

A mole of sodium atoms

A mole of potassium ions

A mole of hydrogen

 Loading...

2. Calculate the number of moles of CaCO₃ (Formula weight = 100) in a sample that weighs 25.0 grams.

0.25

0.75

1.00

0.5

 Loading...

3. Water (H₂O) is a common compound made up of:

3 elements and a total of 3 atoms

2 elements and a total of 3 atoms

3 elements and a total of 2 atoms

2 elements and a total of 2 atoms

 Loading...

4. If Na is Avogadro’s number, then number of valence electrons in 4.2 g of nitride ions N³¯ is

1.6 Na

3.2 Na

2.4 Na

4.2 Na

 Loading...

5. To differentiate between C-12, C-13 and C-14, the instrument that you would use is

Infra-red spectrometer

Ultraviolet spectrometer

Mass spectrometer

Atomic absorption spectrometer

 Loading...

6. If the empirical formula of compound is CH₂. Which of the following is true about its molecular formula?

Its molecular formula does not exist

More than one could be a molecular formula for CH₂

Only one molecular formula (C2H2) is possible

Only one molecular formula (CH2) is possible

 Loading...

7. Which of the following represents an element?

A pure substance made up of one type of atom

A pure substance made up of two or more types of atoms

The periodic table

A compound made up of one type of element

 Loading...

8. Which of the following statements is FALSE for the chemical equation given below in which nitrogen gas reacts with hydrogen gas to form ammonia gas assuming the reaction goes to completion?
N₂ + 3H₂ → 2NH₃

The reaction of one mole of H₂ will produce 2/3 moles of NH₃.

One moles of N₂ will produce two moles of NH₃.

The reaction of three moles of hydrogen gas will produce 17 g of ammonia

One molecule of nitrogen requires three molecules of hydrogen for complete reaction.

 Loading...

9. What are the two different types of ions?

Polyatomic and compound ions

Electrons and protons

Negative and positive

Polyatomic and multivalent

 Loading...

10. Since atoms are neutral, the number of electrons is equal to the number of:

Protons

Nucleus

Neutrons

Ions

 Loading...

11. Which law directly explains the law of conservation of mass?

Dalton’s law

Moley’s law

Hund’s rule

Newton’s law

 Loading...

12. An anhydrous salt of copper is found to contain 52.7% chlorine and 47.3% copper by mass. What is the empirical formula for this salt?

CuCl₂

CuCl

CuCl₃

Cu₂Cl₃

 Loading...

13. Empirical formula of chloroform is

CHCl₃

CH₂C₁₂

CH₃cl

CHCl

 Loading...

14. Which of the following is NOT true of matter on the Earth?

Matter always consists of molecules

Matter is always composed of atoms

All substances are made of matter

All matter contains chemical elements

 Loading...

15. What are the ratios among the volumes of gases of ³²O₂,²H₂, and ¹⁶CH₄ if equal mass of each gas is taken?

2:16:2

2:16:1

1:1:1

1:16:2

 Loading...

16. Ayesha required an aqueous solution of sodium chloride. She made the solution by dissolving salt in:

Air

Water

Oxygen gas

Vinegar

 Loading...

17. Balance the following equation using minimum integral coefficients: (NH₃ + O₂ → NO₂ + H₂O) Find the stoichiometric coefficient for oxygen gas O₂:

4

3

1

7

 Loading...

18. What do you call pure substances that are formed from the attraction between positive ions and negative ions?

Ionic element

Ionic charges

Ionic compounds

Ionic atoms

 Loading...

19. Isotopes differ in the

Number of neutrons

Number of electrons

Number of protons

Number of atoms

 Loading...

20. How many moles of Helium gas occupy 22.4 L at 0°C at 1 atm. Pressure?

1.0

1.11

0.90

0.11

 Loading...

21. Vapor density of a gas is 22. What is its molecular mass?

44

22

33

11

 Loading...

22. The hydrogen phosphate of certain metal has formula MHPO₄. The formula of metal chloride would be

M₂C1₂

MC1₃

MC1

MCL₂

 Loading...

23. Percent of calcium in calcium carbonate is

30%

20%

40%

80%

 Loading...

24. How can you separate the mixture of two gases of different atomic masses?

Crystallization

Sublimation

Graham’s Law of diffusion

Chromatography

 Loading...

25. Indicate the incorrect statement form the following

The empirical and molecular formula of some of the compounds are same

Stoichiometric calculation can only be done if no side reaction happen

A limiting reactant is used at the end of reaction

Actual yield is always less than theoretical yield

 Loading...

Page 2 of 3

26. 1 mole of CH₄ contains

4 g-atom of hydrogen

3.0 g of carbon

1.81 x 10²³ molecules of CH₄

6.02 x 10²³ atoms of H

 Loading...

27. What are the parts of an atom?

Nucleus, element, carbon, space

Ions, electrons, neutrons, water

Protons, neutrons, nucleus, mass

Protons, neutrons, electrons, nucleus

 Loading...

28. Irrespective of the source, pure sample of water always yields 88.89% mass of oxygen and 11.11% mass of hydrogen. This is explained by the law of

Conservation of mass

Definite proportions

Multiple proportions

Constant volume

 Loading...

29. How many elements are present in two molecules of aspirin? The formula for aspirin is C₉H₈O₄.

21

6

3

42

 Loading...

30. Most atoms are neutral, to become a positive ion the atom must:

None of these

Lose electrons and protons

Gain electrons and protons

Lose electrons

 Loading...

31. Which of the following could be an empirical formula?

BaO₂

H₂O₂

C₆H₁₂O₆

C₂H₄

 Loading...

32. Calculate the weight, in grams, of one molecule of carbon dioxide, CO₂.

1.99 x 10¯²³

4.65 x 10¯²³

1.37 x 10²²

7.31 x 10¯²³

 Loading...

33. Among the following pairs, the one which illustrates the law of multiple proportions is

H₂S, SO₂

CuO, Cu₂O

NH₃, HC1

CS₂, FeSO₄

 Loading...

34. Bromine has two isotopes having the relative abundances as ⁷⁵₃₉Br = 50.51% and ⁸¹₃₅Br= 49.49%. The average atomic mass of bromine is

80

79

79.5

81

 Loading...

35. The coefficient of viscosity η of a fluid moving steadily between two surfaces is given by the formula, f = η dV/dx where f is the frictional force on the fluid. A is an area in the fluid and dV/dx is the velocity gradient inside the fluid at that area. The S.I. unit of viscosity coefficient η is given as,

Kg m¯¹s¯¹

Newton

Nm¯²s¯²

Nil, it is dimensionless constant

 Loading...

36. The volume occupied by 28 gram of N₂ at STP?

22.4 dm³

1.12 dm³

112 Cm³

2.24 dm³

 Loading...

37. Which of the following is NOT a pure substance?

Sodium Chloride

Water

Soil

Gold

 Loading...

38. Copper (II) oxide is mixed with organic compound during combustion. The purpose is

To carry out compete combustion

To reduce the time for completion of the reaction

To reduce the economy of the process

All of these

 Loading...

39. How do you calculate the number of neutrons in an atom?

The atomic mass plus the number of protons

The atomic mass subtracted the number of protons

The atomic mass plus the number of electrons

The atomic mass subtracted the number of electrons

 Loading...

40. What is correct relationship between empirical and molecular formulas?

Molecular formula /n = Empirical formula

Empirical formula /n = Molecular formula

Empirical formula x √n = Molecular formula

Empirical formula x n² = Molecular formula

 Loading...

41. What does the atomic number of an atom represent?

Neutrons and electrons

Protons and electrons

Protons and neutrons

Electrons and shells

 Loading...

42. Difference in density is the basis of

Ultrafiltration

Gravity separation

Molecular attraction

Molecular sieving

 Loading...

43. The modern atomic weight scale is based on

H¹

O¹⁶

C¹³

C¹²

 Loading...

44. A compound contains 6.0 g of carbon and 1.0 g of hydrogen. The percent composition of the compound is:

17% hydrogen and 83% carbon

83% hydrogen and 17% carbon

86% hydrogen and 14% carbon

14% hydrogen and 86% carbon

 Loading...

45. For which of the following terms empirical formula cannot be applied?

It can be applied to all

H₂O

CC1₄

NaC1

 Loading...

46. The set of numerical coefficients that balances the chemical equation K₂CrO₄ + CH1 → K₂Cr₂O₇ + KC1 + H₂O

2, 2, 1, 1, 1

1, 1, 2, 2, 1

2, 2, 1, 2, 1

2, 1, 1, 2, 1

 Loading...

47. Which of the following is a pure substance made up of two or more types of atoms or elements?

Compound

Element

Crystal

Mixture

 Loading...

48. Which of the following statements is wrong about isotopes?

They possess different mass number

They possess same position in the periodic table

They possess same physical properties

They possess same chemical properties

 Loading...

49. Which of the following represents a compound?

A pure substance made up of one type of atom

Two words in one word

Pure substances made up to of 2 or more types of atoms

Made up of 10 atoms

 Loading...

50. The compound having highest percent of oxygen is

H₂O

C₂H₅OH

CH₃COCH₃

CH₃COOH

 Loading...

Page 3 of 3

51. The percentage of oxygen in NaOH is

10

8

40

60

 Loading...

52. Diameter of an atom is in the range of

0.2 Pm

2 x10¯¹⁰

0.2 m

0.2 nm

 Loading...

53. How many moles of CO₂ are present in 220 mg?

10 moles

0.005 mole

5 moles

5000 mole

 Loading...

54. What is the percent water in hydrated calcium chloride (CaC1₂ 2H₂O)?

12.26%

24.51%

66.67%

32.47%

 Loading...

55. What is the net charge on ferrous ion?

+4

+5

+3

+2

 Loading...

56. The empirical formula of the compound having 50% sulphur and 50% oxygen by mass is

SO

SO₃

SO₂

S₂O₃

 Loading...

57. One of the substances is used to absorb CO₂ gas in combustion analysis. Which is that substance?

Al₂O₃

KOH

Mg(ClO₄)₂

SiO₂

 Loading...

58. Which of the following method is used to estimate oxygen in an organic compound?

All of above

K. Jeldahl’s method

Combustion method

Duma’s method

 Loading...

59. Which of the following is an element?

Sugar

Water

Common Salt

Gold

 Loading...

60. A gaseous mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture?

20.05%

50%

19.97%

80.03%

 Loading...

61. How many number of ions are there in 98 grams of sulphate ions?

4 x 6.02 x 10²³

6.02 x 10²³ x 2

6.02 x 10²³

3 x 6.02 x 10²³

 Loading...

62. The empirical formula of a compound is CH₂O and its molecular mass is 120. The molecular formula of the compound is

C₃H₆O₃

CH₂O

C₄H₈O₄

C₂H₄O₂

 Loading...

63. How will you separate a mixture of two gases?

Chromatography

Graham’s law of diffusion technique

Osmosis

Fractional distillation technique

 Loading...

64. What is a multivalent ion?

Only negatively charged

Ions that are made of more than one type of atom and act as one

An ion that can have more than one charge

Some ions can have only one charge

 Loading...

65. The prefix 10¹⁸ is

Kilo

Nano

Giga

Exa

 Loading...

66. What is a chemical compound?

A combination of two or more chemical elements

A mixture of two or more substance

A subatomic particle

A combination of two protons and two electrons

 Loading...

67. The Number of oxygen atoms in 4.4 g of CO2 is approximately

6 x 10²²

6 x 10²²

1.2 x 10²³

12 x 10²³

 Loading...

68. Molecular compounds can be found in all three states of matter at room temperature. Which molecule compound is a liquid at room temperature?

Sugar

Carbon dioxide

Methane

Water

 Loading...

69. A ring contains 1.2g of diamond. How many number of carbon atoms are in diamond?

6.02 x 10²³

6.02 x 10²²

3.01 x 10²³

3.01 x 10²²

 Loading...

70. An oxide of nitrogen contain 36.8% nitrogen and 63.2% oxygen by mass. Calculate its empirical formula.

NO

N₂O

N₂O₃

NO₂

 Loading...

71. How many moles of KBrO₃ are required to prepare 0.0700 moles of Br₂ according to the reaction: KBrO₃ + 5KBr + 6HNO₃ → 6KNO₃ + 3Br₂ + 3H₂O

0.0732

0.210

0.0233

0.0704

 Loading...

 Loading...

• <<
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31
• 32
• 33
• 34
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• 45
• 46
• 47
• 48
• 49
• 50
• 51
• 52
• 53
• 54
• 55
• 56
• 57
• 58
• 59
• 60
• 61
• 62
• 63
• 64
• 65
• 66
• 67
• 68
• 69
• 70
• 71
• >>