CHEMISTRY
THE PRESENCE OF UNPAIRED ELECTRONS IN AN ATOM OF A TRANSITION METAL GIVES RISE TO
A. paramagnetism ✓ B. malleability C. ductility D. shiny appearance The presence of unpaired electrons in an atom of a transition metal gives rise to paramagnetism. Paramagnetism is a form of magnetism that occurs only in the presence of an external…
HOW MANY ATOMS OF CHLORINE ARE REQUIRED TO SATURATE THE DOUBLE BONDS OF A COMPOUND CONTAINING A TRIENE
A. 2 B. 3 C. 4 D. 5 E. 6 ✓ To determine the number of atoms of chlorine required to saturate the double bonds of a compound containing a triene, we first need to understand the structure of a triene. A triene…
A BASIC POSTULATE OF THE KINETIC THEORY OF GASES IS THAT THE MOLECULES OF A GAS MOVE IN STRAIGHT LINES BETWEEN COLLISIONS. THIS IMPLIES THAT
A. collisions are perfectly elastic ✓ B. forces of repulsion exist C. forces of repulsion and attraction are in equilibrium D. collisions are inelastic Collisions are elastic in the context of the kinetic theory of gases does not imply that collisions are…
ACCORDING TO CHARLES’ LAW, THE VOLUME OF A GAS BECOMES ZERO AT
A. 0°C B. -100°C C. -273°C ✓ D. -373°C Charles’ law states that the volume of a gas is directly proportional to its absolute temperature, provided that the pressure remains constant. Absolute temperature is measured in Kelvin (K), which is based on…
AN UNSATURATED SOLUTION DIFFERS FROM A SATURATED SOLUTION AT A GIVEN TEMPERATURE BECAUSE IT
A. Cannot dissolve more solute B. Can hold more solute than it can actually dissolve C. Can still dissolve more solute at given temperature ✓ D. Form crystal more easily on cooling An unsaturated solution differs from a saturated solution at a…
ALUMINIUM IS USED IN THE MANUFACTURE OF AIRCRAFT BECAUSE IT
A. Is hard and brittle B. Is light and resists corrosion ✓ C. Has high density and conducts electricity D. Is malleable and ductile Aluminium is chosen for aircraft construction due to its advantageous properties. Firstly, aluminium is lightweight, which helps reduce…
THE ENERGY CHANGE THAT ACCOMPANIES THE ADDITION OF AN ELECTRON TO AN ISOLATED GASEOUS ATOM IS
A. bond energy B. electronegativity C. electron affinity ✓ D. ionization energy When an electron is added to an isolated gaseous atom, the energy change that occurs is known as the electron affinity. Electron affinity is defined as the energy released or…
HOW MANY ISOTOPES HAS HYDROGEN
A. 2 B. 3 ✓ C. 4 D. 5 Hydrogen, the first element on the periodic table, has three naturally occurring isotopes. These isotopes are sometimes denoted as 1H, 2H, and 3H. Among these isotopes, 1H and 2H are stable, while 3H is radioactive with a half-life of 12.32 years. Protium…
SPECIES THAT OCCUR IN A REACTION PATHWAY BUT NOT IN THE OVERALL REACTION ARE KNOWN AS
A. Reactants B. Inhibitors C. Products D. Intermediates ✓ In a chemical reaction, species that occur in a reaction pathway but not in the overall reaction are known as intermediates. These intermediates are the transient chemical species that are formed during the reaction…
A MIXTURE CONTAINING TWO SALTS OF DIFFERENT SOLUBILITY CAN BE SEPARATED BY
A. chromatography B. crystallization ✓ C. distillation D. evaporation Crystallization is the most suitable method for separating a mixture containing two salts of different solubility. This technique takes advantage of the varying solubilities of the salts in a solvent. When…
DILUTE TRIOXONITRATE (V) ACID DOES NOT PRODUCE HYDROGEN WHEN IT REACTS WITH METALS BECAUSE
A. it reacts with the product B. it is highly corrosive C. there is no visible reaction D. it is a strong oxidizing agent ✓ When dilute trioxonitrate (V) acid, also known as nitric acid, reacts with metals, it…
THE FORMATION OF A BOND BETWEEN HYDROGEN AND A HIGHLY ELECTRONEGATIVE ATOM RESULTS IN
A. polarity ✓ B. electrovalent bond C. dipole D. metallic bond When hydrogen forms a bond with a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F), it results in polarity. This is because the highly electronegative atom…
ALKENES CAN BE MANUFACTURED BY
A. the combustion of alkanes B. the cracking of hydrocarbons ✓ C. polymerization reactions D. addition of hydrogen to unsaturated vegetable oils Cracking is a chemical process used in petroleum refining to break down larger hydrocarbon molecules into smaller…
NITROGEN OBTAINED FROM THE LIQUEFACTION OF AIR HAS A HIGHER DENSITY THAN THAT OBTAINED FROM NITROGEN CONTAINING COMPOUNDS BECAUSE THE FORMER CONTAINS
A. water vapour B. oxygen C. carbon (IV) oxide D. rare gases ✓ Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen-containing compounds because the former contains rare gases. When nitrogen is obtained through the…
WHICH OF THE FOLLOWING WILL HAVE ITS MASS INCREASED WHEN HEATED IN AIR
A. Helium B. Magnesium ✓ C. Copper pyrites D. Glass When heated in air, magnesium will undergo a chemical reaction known as combustion. During this process, magnesium reacts with oxygen in the air to form magnesium oxide. The mass of the magnesium…
THE LANTHANIDES AND ACTINIDES ARE LOCATED IN WHICH BLOCK OF THE PERIODIC TABLE
A. P-block B. S-block C. F-block ✓ D. D-block The answer to the question is: C. F-block The lanthanides and actinides are located in the f-block of the periodic table. These two series of elements are often referred to as the inner transition metals.…
WHAT IS THE MAXIMUM NUMBER OF ELECTRONS THAT AN F-ORBITAL CAN ACCOMMODATE
A. 2 B. 6 C. 7 D. 10 E. 14 ✓ The answer to the question is: E. 14 The f-orbital is one of the types of atomic orbitals in quantum mechanics, which describes the wave-like behavior of electrons in an atom. Each…
HOW MANY ZONES ARE PRESENT IN A LUMINOUS BUNSEN BURNER FLAME
A. 2 B. 3 C. 4 ✓ D. 5 E. 6 The answer to the question is: C. 4 In a luminous Bunsen burner flame, there are four zones present. These zones are crucial to understanding the different regions within the flame and their characteristics.…
THE USE OF SULPHUR TO VULCANIZE RUBBER IS MADE TO MAKE IT
A. blacker. B. cheaper. C. more elastic D. tougher ✓ E. softer. The answer to the question is: D. tougher Vulcanization is a chemical process that involves adding sulphur to rubber to improve its properties. The addition of sulphur cross-links the…
THE ATOMIC NUMBER OF IRON IS 26. THE NUMBER OF UNPAIRED ELECTRONS IN THE FE3+ ION IS
A. 1 B. 2 C. 3 D. 4 E. 5 ✓ The answer to the question is: E. 5 To determine the number of unpaired electrons in the Fe3+ ion, we need to understand the electronic configuration of iron (Fe) and how it…
ANIMAL CHARCOAL DIFFERS FROM WOOD CHARCOAL IN THAT IT
A. has a dark colour B. has a high carbon content C. is a good absorbent ✓ D. is crystalline. E. is rich in phosphate content The answer to the question is: C. is a good absorbent Animal charcoal differs from wood charcoal…
AMMONIUM SALTS
Ammonium salts are prepared by dissolving ammonia in the appropriate acid or neutralising aqueous ammonia with the appropriate acid. The ammonium salts are then separated out of the solution by crystallisation and not by evaporation because they are heat-liable. e.g.…
OXIDES
Oxides are binary compounds formed when elements combine with oxygen. Binary compounds are compounds containing two elements only. Oxides are classified into several groups, namely, acidic oxides, basic oxides, amphoteric oxides, neutral oxides and higher oxides. 1) Acidic oxides: These…
IODINE
Iodine was discovered in 1812 by Courtois. Iodides occur in minute quantities in sea water. They are also found as organic compounds in some sea weeds and as deposits of sodium (NaIO3)and calcium trioxoiodates (V), (Ca (IO3)2) in association with…
GRAPHITE
Graphite exists as black, slippery, hexagonal crystals. The carbon atoms in graphite, form flat layers, and are joined together by strong covalent bonds. These layers are arranged in parallel, one above the other, with weak intermolecular forces operating in-between the…
INTRODUCTION TO CARBON
Carbon occurs naturally as diamond and graphite. It also occurs in an impure form as coal and in the combined state as carbon (IV) oxide, natural gas, petroleum and wood. Other sources of carbon are mineral deposits of metallic trioxocarbonates…
DIAMOND
Diamond is the purest form of naturally occuring carbon. It is found as colourless, lustreless solids which can be transformed into brilliant gems. It consists of an array of bonded atoms. No discrete molecules can be distinguished. Diamond crystal is…
OZONE
Ozone is an unstable triatomic molecule of oxygen. In 1866, J. Soret, demonstrated that ozone was an allotrope of oxygen. Ozone is formed from atmospheric oxygen by lightning flashes. Small fractions of ozone are also formed around electrical machinery when…
OCTANE NUMBER
Octane number (octane rating) is a measure of the performance of petrol in the engine and the rating depends on the percentage composition of branched chain (iso-octane) to straight chain (n – pentane) hydrocarbons in the fuel. Petrol consists of…
CRACKING AND REFORMING
CRACKING Cracking is the process of further treatment of crude oil fractions in which bigger hydrocarbon fractions are broken down into smaller hydrocarbon fractions. It consists of heating the hydrocarbons in the C 15- and- above range under high pressure…
MATTER
Science interprets nature in terms of energy and matter. Matter, the material of which the universe is composed, may be defined as anything that has mass and occupies space. Mass is a measure of quantity of matter. The mass of…
INTRODUCTION TO CHEMISTRY
Chemistry may be defined as the science that is concerned with the composition and the structure of matter, and with the forces that hold the structures together. Chemistry as a science has, as its primary objectives, the determination of the…
ETHICAL, LEGAL AND SOCIAL ISSUES IN CHEMISTRY
The study of chemistry has brought tremendous, positive development to the world and to Nigeria in particular. Chemistry has contributed greatly towards providing our basic needs and improving the quality of our life. For example, the provision of clothing, housing,…
