NSMQ

NSMQ 2026 Chemistry Speed Race

Given that the bond enthalpy of H-H is 436 kJ/mol, F-F is 158 kJ/mol and H-F is 568 kJ/mol, calculate the enthalpy change for the reaction H₂(g) + F₂(g) ⇌ 2HF(g).

Question 2

A hydrated magnesium chloride contains water of hydration of mass equal to that of the anhydrous salt.

Question 3

Give the systematic name of an organic compound with the molecular formula C₃H₆O that does not react with Tollen's reagent.

Question 4

Calculate the percentage by mass of nitrogen in ammonium sulfate.

Question 5

What volume of 0.150 mol/dm³ H₂SO₄ is required to neutralise 25.0 cm³ of 0.300 mol/dm³ NaOH?

Question 6

What is the mass of one mole of potassium methanoate?

Question 7

What volume of 12.0 mol/dm³ stock H₂SO₄ is required to prepare exactly 500.0 cm³ of a 0.600 mol/dm³ H₂SO₄ solution?

Question 8

At a certain temperature, the reaction 2A(g) ⇌ B(g) has a Kc of 50.0. If the equilibrium concentration of A is 0.200 mol/dm³, find the equilibrium concentration of B.

Question 9

A compound contains 12.0% carbon, 16.0% oxygen and 72% chlorine. Determine its molecular formula if its molar mass is 198 g/mol.

Question 10

Calculate the mass of potassium carbonate required to prepare 250.0 cm³ of a 0.200 M solution.

Question 11

The vapour pressure of chemically pure water is 3.00 kPa at a certain temperature. What is the vapour pressure of a solution in which the mole fraction of water is 0.900?

Question 12

Determine the empirical formula of an oxide of element X that contains 30.4% by mass of X, given that the atomic mass of X is 14 g/mol.

Question 13

A 5.60 dm³ rigid vessel at STP contains a mixture of ideal gas. How many gas molecules are contained in the vessel?

Question 14

A 12.0 g sample of an impure hydrated metal salt is heated intensely until all the water is expelled. The final dry anhydrous salt weighs exactly 6.40 g. Calculate the mass percent of water in the original hydrated crystal sample.

Question 15

A radioisotope decays from 12.8 g to 0.10 g in 2.2 hours. What is the half-life of the radioisotope in minutes?

Question 16

A gas occupies 4.00 dm³ at 300.0 K and 100.0 kPa. What is its volume at 400.0 K and 200.0 kPa?

Question 17

Element M has two isotopes, M-63 with relative abundance 69% and M-65 with relative abundance 31%. Calculate the relative atomic mass of M.

Question 18

In a titration, 40.0 cm³ of 0.10 mol/dm³ NaOH reacts with 60.0 cm³ of 0.20 mol/dm³ HCl. What is the concentration of the unreacted HCl?

Question 19

If 56.0 g of nitrogen gas react completely with excess hydrogen, what mass of ammonia gas is formed?

Question 20

How many atoms are in 4.6 g of nitrogen dioxide?

Question 21

Calculate the pH of a buffer system formed from 0.0087 mol/dm³ of a weak acid of Ka 1.0 × 10⁻³ and 0.87 mol/dm³ of its salt.

Question 22

Question 23

Question 24

Question 25

Question 26

Question 27

Question 28

Question 29

Question 30

Question 31

Question 32

Question 33

Question 34

Question 35

Question 36

Question 37

Question 38

Question 39

Question 40

Question 41

Question 42

Question 43

Question 44

Question 45

Question 46

Question 47

Question 48

Question 49

Question 50

Question 51

Question 52

Question 53

Question 54

Question 55

Question 56

Question 57

Question 58

Question 59

Question 60

Question 61

Question 62

Question 63

Question 64

Question 65

Question 66

Question 67

Question 68

Question 69

Question 70

Question 71

Question 72

Question 73

Question 74

Question 75

Question 76

Question 77

Question 78

Question 79

Question 80

Question 81

Question 82

Question 83

Question 84

Question 85

Question 86

Question 87

Question 88

Question 89

Question 90

Question 91

Question 92

Question 93

Question 94

Question 95

Question 96

Question 97

Question 98

Question 99

Question 100

Question 101

Question 102

Question 103

Question 104

Question 105

Question 106

Question 107

Question 108

Question 109

Question 110

Question 111

Question 112

Question 113

Question 114