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MDCAT Fundamental Concepts of Chemistry Online Test

Umaima Harmain RaoLast Updated: May 24, 2025

Chemistry Basic Concepts MCQS Online Test

MDCAT Chemistry Basic Concepts Chapter Online Test

Total Questions:	71
Time Allowed:	30 Minutes
Total Marks:	71
How to Attempt Test:	Please choose the right Option in MCQ-type question.
Test Helpful For:	MDCAT Entry Test Chemistry Online Test Interview Questions about Chemisttry All Universities Entrance Test Recruitments Tests

MDCAT Chemistry Basic Concepts Test

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Page 1 of 3

Chemistry

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

BaO₂

H₂O₂

C₆H₁₂O₆

C₂H₄

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

20.05%

80.03%

19.97%

50%

3. What are the two different types of ions?

Negative and positive

Polyatomic and multivalent

Polyatomic and compound ions

Electrons and protons

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

4.65 x 10¯²³

1.37 x 10²²

7.31 x 10¯²³

1.99 x 10¯²³

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

They possess same chemical properties

They possess same physical properties

They possess different mass number

They possess same position in the periodic table

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

To carry out compete combustion

All of these

To reduce the time for completion of the reaction

To reduce the economy of the process

7. 1 mole of CH₄ contains

3.0 g of carbon

6.02 x 10²³ atoms of H

1.81 x 10²³ molecules of CH₄

4 g-atom of hydrogen

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

S₂O₃

SO₃

SO₂

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

SiO₂

Al₂O₃

KOH

Mg(ClO₄)₂

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

79.5

11. 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

One moles of N₂ will produce two moles of NH₃.

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

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

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

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

2, 1, 1, 2, 1

2, 2, 1, 2, 1

2, 2, 1, 1, 1

1, 1, 2, 2, 1

13. The percentage of oxygen in NaOH is

14. 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

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

All substances are made of matter

Matter is always composed of atoms

Matter always consists of molecules

All matter contains chemical elements

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

More than one could be a molecular formula for CH₂

Its molecular formula does not exist

Only one molecular formula (CH2) is possible

Only one molecular formula (C2H2) is possible

17. 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,

Nil, it is dimensionless constant

Nm¯²s¯²

Kg m¯¹s¯¹

Newton

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

Fractional distillation technique

Chromatography

Graham’s law of diffusion technique

Osmosis

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

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

All of above

Duma’s method

K. Jeldahl’s method

Combustion method

21. What is the net charge on ferrous ion?

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

Compound

Crystal

Element

Mixture

23. Empirical formula of chloroform is

CH₂C₁₂

CHCl₃

CH₃cl

CHCl

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

It can be applied to all

CC1₄

NaC1

H₂O

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

Dalton’s law

Newton’s law

Hund’s rule

Moley’s law

Page 2 of 3

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

6.02 x 10²²

3.01 x 10²³

3.01 x 10²²

6.02 x 10²³

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

The atomic mass subtracted the number of protons

The atomic mass subtracted the number of electrons

The atomic mass plus the number of protons

The atomic mass plus the number of electrons

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

Gain electrons and protons

None of these

Lose electrons

Lose electrons and protons

29. The modern atomic weight scale is based on

C¹²

H¹

C¹³

O¹⁶

30. The compound having highest percent of oxygen is

C₂H₅OH

H₂O

CH₃COCH₃

CH₃COOH

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

Ionic atoms

Ionic charges

Ionic compounds

Ionic element

32. Indicate the incorrect statement form the following

A limiting reactant is used at the end of reaction

Actual yield is always less than theoretical yield

Stoichiometric calculation can only be done if no side reaction happen

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

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

MC1

M₂C1₂

MC1₃

MCL₂

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

Nucleus

Neutrons

Protons

Ions

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

Electrons and shells

Neutrons and electrons

Protons and electrons

Protons and neutrons

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

37. Which of the following represents an element?

A compound made up of one type of element

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

A pure substance made up of one type of atom

The periodic table

38. 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?

CuCl₃

CuCl₂

Cu₂Cl₃

CuCl

39. What is a chemical compound?

A subatomic particle

A mixture of two or more substance

A combination of two protons and two electrons

A combination of two or more chemical elements

40. Which one of the following is ambiguous?

A mole of potassium ions

A mole of sodium atoms

A mole of hydrogen

A mole of electrons

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

1.2 x 10²³

6 x 10²²

12 x 10²³

6 x 10²²

42. Difference in density is the basis of

Molecular attraction

Ultrafiltration

Molecular sieving

Gravity separation

43. What are the parts of an atom?

Nucleus, element, carbon, space

Protons, neutrons, nucleus, mass

Protons, neutrons, electrons, nucleus

Ions, electrons, neutrons, water

44. 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

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

46. Diameter of an atom is in the range of

2 x10¯¹⁰

0.2 nm

0.2 m

0.2 Pm

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

Sugar

Methane

Carbon dioxide

Water

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

Graham’s Law of diffusion

Chromatography

Sublimation

Crystallization

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

2:16:1

1:16:2

2:16:2

1:1:1

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

0.5

0.75

0.25

1.00

Page 3 of 3

51. Isotopes differ in the

Number of atoms

Number of neutrons

Number of electrons

Number of protons

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

0.0233

0.0704

0.0732

0.210

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

1.12 dm³

112 Cm³

2.24 dm³

22.4 dm³

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

Water

Air

Oxygen gas

Vinegar

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

66.67%

12.26%

32.47%

24.51%

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

4 x 6.02 x 10²³

6.02 x 10²³

3 x 6.02 x 10²³

6.02 x 10²³ x 2

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

C₄H₈O₄

C₂H₄O₂

C₃H₆O₃

CH₂O

58. Which of the following represents a compound?

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

Made up of 10 atoms

Two words in one word

A pure substance made up of one type of atom

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

Sodium Chloride

Water

Soil

Gold

60. Which of the following is an element?

Water

Gold

Common Salt

Sugar

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

1.11

1.0

0.90

0.11

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

H₂S, SO₂

CS₂, FeSO₄

CuO, Cu₂O

NH₃, HC1

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

Molecular formula /n = Empirical formula

Empirical formula /n = Molecular formula

Empirical formula x n² = Molecular formula

Empirical formula x √n = Molecular formula

64. Percent of calcium in calcium carbonate is

20%

30%

40%

80%

65. 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

Multiple proportions

Constant volume

Conservation of mass

Definite proportions

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

3 elements and a total of 2 atoms

2 elements and a total of 2 atoms

2 elements and a total of 3 atoms

3 elements and a total of 3 atoms

67. 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

14% hydrogen and 86% carbon

83% hydrogen and 17% carbon

86% hydrogen and 14% carbon

68. What is a multivalent ion?

Some ions can have only one charge

An ion that can have more than one charge

Only negatively charged

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

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

N₂O

NO₂

N₂O₃

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

5000 mole

5 moles

0.005 mole

10 moles

71. The prefix 10¹⁸ is

Giga

Exa

Nano

Kilo

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Umaima Harmain RaoLast Updated: May 24, 2025

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15 Comments

jaweria says:

November 9, 2022 at 5:11 pm

Got 97 %

Rom says:

September 4, 2021 at 6:55 pm

No bro the right ans is what is in test bcz *n* integer must be multiplied with E F to form MF and when it go towards other side it will be as a denominator of MF.

Saira sahfi says:

August 16, 2021 at 8:26 pm

Good experience and good practice test is very nice entry test practice .

1. Saira shafi says:
  
  August 16, 2021 at 8:30 pm
  
  Good experience test
  
Tarique Hussain says:

July 15, 2021 at 9:18 pm

Sir question to show nhn ho rhy hn

RK Durrani says:

August 29, 2020 at 7:39 am

Too much helpful for preparation

m.umair says:

August 21, 2020 at 9:21 am

Just want improvement

Rajab Ali says:

July 5, 2017 at 1:08 pm

Got 95%

1. Sara says:
  
  June 24, 2021 at 8:04 pm
  
  Did you get admission in medical college?
  
Afifa zahid says:

August 20, 2016 at 10:01 pm

Absolutely,mine the 1st most qs is wrong,now i am not going to give this test

zubair khalid says:

August 17, 2016 at 1:35 am

question no. 19 is incorrect plzz correct it….

zubair khalid says:

August 17, 2016 at 1:33 am

EMPIRICAL FORMULA/n=molecular formula it’s the correct answer but they concider it as wrong what a LOL..

1. NotSuitableHere says:
  
  August 26, 2021 at 9:05 am
  
  You are wrong man, they are correct.
  
2. Rom says:
  
  September 4, 2021 at 6:54 pm
  
  No bro the right ans is what is in test bcz *n* integer must be multiplied with E F to form MF and when it go towards other side it will be as a denominator of MF.
  
3. Erana emra says:
  
  April 26, 2022 at 11:54 pm
  
  Broo it is
  Molecular formula = n ( emperical formula)
  Soo….
  MF/n = emperical formula

MDCAT Fundamental Concepts of Chemistry Online Test

Chemistry Basic Concepts MCQS Online Test

MDCAT Chemistry Basic Concepts Chapter Online Test

MDCAT Chemistry Basic Concepts Test

Chemistry

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Umaima Harmain Rao

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Chemistry Basic Concepts MCQS Online Test

MDCAT Chemistry Basic Concepts Chapter Online Test

MDCAT Chemistry Basic Concepts Test

Chemistry

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Umaima Harmain Rao

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