What happens to the position of equilibrium, if a reversible exothermic reaction is subjected to a decrease in temperature?
Απάντηση
(B)
The position of equilibrium shifts to the right.
2
Which noble gas is radioactive and is produced as a decay product of uranium and thorium?
Απάντηση
(C)
Radon
3
Which of the following reactions would be expected to have the highest entropy change?
Απάντηση
(A)
Liquid → Gas
4
What is the sum of the oxidation numbers in a neutral compound?
Απάντηση
(C)
0
5
According to the kinetic theory of gases, the pressure exerted by a gas is due to
Απάντηση
(D)
The collisions of gas particles with the container walls
6
What is eutrophication?
Απάντηση
(B)
The excessive growth of algae due to nutrient enrichment
7
What is the name of the process by which ammonia is produced on an industrial scale?
Απάντηση
(D)
Haber process
8
Who proposed the planetary model of the atom with electrons orbiting the nucleus?
Απάντηση
(B)
Ernest Rutherford
9
Which of the following is an example of an endothermic reaction?
Απάντηση
(C)
Formation of table salt (NaCl) from sodium (Na) and chlorine (Cl\(_2\)).
10
What happens to the value of the equilibrium constant (Kc) for a reaction if the reaction is reversed?
Απάντηση
(D)
It becomes the reciprocal of the original value
11
What is the chemical structure of soap and detergent molecules?
Απάντηση
(A)
Hydrophilic head and hydrophobic tail
12
What is the solubility product constant (Ksp) used for?
Απάντηση
(B)
To determine the concentration of a solute in a saturated solution
13
Which trace gas in the atmosphere plays a significant role in the greenhouse effect?
Απάντηση
(C)
Carbon dioxide
14
Which of the following methods can be used to remove temporary hardness from water?
Απάντηση
(A)
Boiling
15
What is Faraday's constant?
Απάντηση
(D)
96,485 C/mol
16
A gas occupies a volume of 1.5 liters at a pressure of 2 atmospheres. If the pressure is increased to 4 atmospheres while the temperature remains constant, what will be the new volume of the gas?
Απάντηση
(C)
0.75 liters
17
Stainless steel is an alloy made up of
Απάντηση
(C)
Iron and chromium
18
What is the state of matter in which particles are widely spaced and move freely with high kinetic energy?
Απάντηση
(D)
Gas
19
Identify the reducing agent in the following reaction:
Zn + CuSO\(_4\) → ZnSO\(_4\) + Cu
Απάντηση
(B)
Zn
20
Balance the following redox reaction:
Fe\(_2\)O\(_3\) + CO → Fe + CO\(_2\)
Απάντηση
(D)
Fe\(_2\)O\(_3\) + 3CO → 2Fe + 3CO\(_2\)
21
What is the trend for ionization energy across a period in the periodic table?
Απάντηση
(A)
Increases from left to right.
22
Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?
Απάντηση
(A)
Ionic bonding
23
Which of the following alkanes has a straight-chain structure?
Απάντηση
(D)
Pentane (C5H12)
24
What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?
Απάντηση
(B)
Hydrogen gas at the cathode and oxygen gas at the anode
25
When an acidic solution is diluted, what happens to its pH?
Απάντηση
(D)
It increases
26
Which of the following factors does NOT affect the rate of a chemical reaction?
Απάντηση
(C)
Molecular weight of products
27
Which organic compound is responsible for the characteristic aroma of fruits?
Απάντηση
(C)
Ester
28
What is the molar mass of water (H2O)?
Απάντηση
(A)
18 g/mol
29
What is the chemical formula of rust, which is formed on the surface of iron in the presence of oxygen and moisture?
Απάντηση
(D)
Fe\(_2\)O\(_3\)
30
How many pi (\(\pi\)) bonds are there in an alkene with six carbon atoms?
Απάντηση
(A)
1
31
What is the principal ore of iron, from which iron is extracted?
Απάντηση
(D)
Hematite
32
Which group does calcium belong to in the periodic table?
Απάντηση
(A)
Alkaline earth metals
33
Which of the following is a primary constituent of crude oil?
Απάντηση
(D)
Methane
34
What is the main source of carbon monoxide (CO) in urban areas?
Απάντηση
(B)
Vehicle emissions
35
What is the empirical formula of a compound containing 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?
Απάντηση
(B)
CH\(_2\)O
36
Which separation technique is used to separate different pigments in a mixture based on their affinity for a stationary phase and a mobile phase?
Απάντηση
(A)
Chromatography
37
What is the common name for ethanoic acid?
Απάντηση
(A)
Acetic acid
38
What type of reaction is involved in the formation of alkanols from alkenes?
Απάντηση
(D)
Addition reaction
39
What is the mass percentage of carbon (C) in methane (CH4)? (The molar mass of carbon is approximately 12 g/mol.)
Απάντηση
(C)
75%
40
Which of the following is a common property of non-metals?
Απάντηση
(B)
Tend to gain electrons in chemical reactions
41
What is the symbol used to represent an alpha particle?
Απάντηση
(A)
α
42
When a substance is oxidized, it
Απάντηση
(A)
Loses electrons
43
A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?
Απάντηση
(C)
The solution is acidic
44
Which of the following compounds is an example of an electrovalent bond?
Απάντηση
(A)
NaCl (sodium chloride)
45
If gas A has a molar mass of 32 g/mol and gas B has a molar mass of 64 g/mol, what is the ratio of their diffusion rates?
Απάντηση
(A)
2:1
46
The contact process is used for the industrial production of
Απάντηση
(A)
sulfuric acid (H2SO4)
47
Which of the following is a unique property of water compared to other liquids?
Απάντηση
(C)
It expands when freezing
48
Sodium reacts vigorously with water to produce
Απάντηση
(C)
Sodium hydroxide (NaOH) and hydrogen gas (H2)
49
At room temperature and standard pressure, chlorine gas is in which state of matter?
Απάντηση
(D)
Gas
50
What is the molecular geometry of a molecule with three bonding pairs and no lone pairs around the central atom?
Απάντηση
(B)
Trigonal planar
51
Isotopes of an element have
Απάντηση
(A)
The same number of protons but different numbers of neutrons.
52
Which element is placed at the top of the electrochemical series?
Απάντηση
(C)
Sodium
53
Which transition metal is known for its multiple colorful oxidation states and compounds used in pigments and paints?
Απάντηση
(B)
Copper (Cu)
54
Which of the following methods is commonly used to remove suspended impurities from water?
Απάντηση
(C)
Filtration
55
What is the valency of an element with the electronic configuration 2, 8, 7?
Απάντηση
(B)
1
56
When anhydrous cobalt chloride paper is exposed to water, what color change is observed?
Απάντηση
(D)
From blue to pink
57
Which type of salt is found in antacid medications and is used to relieve heartburn and indigestion?
Απάντηση
(B)
Magnesium chloride
58
What is the atomic number of aluminium?
Απάντηση
(A)
13
59
Which of the following metals is commonly alloyed with copper to make brass?
Απάντηση
(D)
Zinc
60
What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?
Απάντηση
(B)
Esterification
61
Which functional group is present in alkanals?
Απάντηση
(A)
Carbonyl group (C=O)
62
At 2.0 atm pressure, the volume of a gas is 4.0 L. If the pressure is reduced to 1.0 atm while keeping the temperature constant, what will be the new volume of the gas?
Απάντηση
(C)
8.0 L
63
What is the main environmental concern associated with sulfur dioxide emissions?
Απάντηση
(A)
Formation of acid rain
64
Benzene can be converted to its derivative toluene by the addition of a methyl group. The reaction is an example of
Απάντηση
(C)
Electrophilic substitution
65
Why is water often referred to as the "universal solvent"?
Απάντηση
(D)
Water can dissolve a wide variety of substances due to its polar nature
66
Which of the following mixtures is an example of a colloid?
Απάντηση
(A)
Milk
67
Which of the following substances is NOT hygroscopic?
Απάντηση
(D)
Aluminum
68
What is the mass (in grams) of 500 mL of ethanol? (density of ethanol = 0.789 g/mL)
Απάντηση
(C)
394.5 g
69
The heat of reaction can be determined experimentally using a device called a
Απάντηση
(A)
Calorimeter
70
Which halogen is a gas at room temperature and is pale yellow in color?
Απάντηση
(B)
Fluorine (F)
71
What unit of temperature should be used when applying the ideal gas law?
Απάντηση
(B)
Kelvin (K)
72
Chlorine gas is commonly used in the production of which of the following industrial compounds?
Απάντηση
(A)
Chlorofluorocarbons (CFCs)
73
The process of rusting is an example of the formation of
Απάντηση
(A)
Basic oxide
74
Which of the following is an example of a primary cell?
Απάντηση
(A)
Alkaline battery
75
Which of the following is a characteristic property of acids?
Απάντηση
(D)
React with metals to produce hydrogen gas
76
The lanthanides and actinides are located in which block of the periodic table?
Απάντηση
(C)
F-block
77
What is the IUPAC name for the compound CCl\(_4\)?
Απάντηση
(B)
Tetrachloromethane
78
Which of the following statements is true regarding the melting and boiling points of pure substances?
Απάντηση
(D)
The melting and boiling points can vary depending on the substance
79
An element has an atomic number of 8 and a mass number of 16. How many neutrons does this element have?
Απάντηση
(C)
8
80
Which of the following statements is true for strong electrolytes?
