NIS NIGERIA IMMIGRATION SERVICE RECRUITMENT CHEMISTRY PAST QUESTIONS
(i) Carbon : A filter with granular activated Carbon is used to remove Certain chemical mostly Organic chemicals from water Carbon is used to remove com chemicals which gives Odors or taste to the water Such as Hydrogen Sulfide.
(ii) chlorine is added to water during treatment in order to kill Parasites bacterias and Viruses and the Process a Called chlorination
(i)Sedimentation: Sedimentation is one of the steps water treatment plants use to separate out solids from the water. During sedimentation, flocs settle to the bottom of the water because they are heavier than water.
(ii)Filtration: Once the flocs have settled to the bottom of the water, the clear water on top is filtered to separate additional solids from the water. During filtration, the clear water passes through filters that have different pore sizes and are made of different materials (such as sand, gravel, and charcoal).
(iii) Disinfection: After the water has been filtered, water treatment plants may add one or more chemical disinfectants (such as chlorine, chloramine, or chlorine dioxide) to kill any remaining parasites, bacteria, or viruses.
Phenolphthalein is used in titration of CH3COOH2 with NA0H2
Because the titration involves weak acid against Strong Base.
When ZnCO3 is Heated Strongly it gives a yellow colour and when it left for few minutes to cool .
It give white colour
First you dissolved the two inside water, the glucose will be dissolved while the starch remain insoluble.
you will then carried out filtration process to obtain starch as to resedure while the glucose remains as crystalloids in the solution
To Obtain the glucose you carried out crystallisation and evaporation then follow by recrystallisation
Coming!!! Pls be Calm
Plutonic rocks are a type of igneous rock that forms when molten rock (magma) cools and solidifies beneath the Earth’s surface. Examples of plutonic rocks include: granite and gabbro.
(i) Mechanically formed sedimentary rocks are formed by the physical processes of weathering and erosion, while chemically formed sedimentary rocks are formed by the chemical processes of precipitation and crystallization.
(ii) Mechanically formed sedimentary rocks have a clastic or fragmented texture, while chemically formed sedimentary rocks have a crystalline or amorphous texture.
(iii) The composition of mechanically formed sedimentary rocks is determined by the type and composition of the source rocks they are derived from, while the composition of chemically formed sedimentary rocks is determined by the chemical reactions that take place during their formation.
(iv) Mechanically formed sedimentary rocks can be formed on or near the Earth’s surface, while chemically formed sedimentary rocks typically form at depth, where the conditions are more conducive to chemical reactions.
(i)The igneous form of rocks does not include any fossil deposits.
(ii)Most igneous forms include more than one mineral deposit.
(iii)They can be either glassy or coarse.
(iv)These usually do not react with acids.
(i) Latitude: The distance of a location from the equator is a major factor that determines its climate. Locations near the equator receive more direct sunlight and have warmer temperatures, while locations farther from the equator are cooler and receive less direct sunlight.
(ii) Altitude: The altitude of a location also affects its climate. Locations at higher elevations are cooler, due to the decrease in atmospheric pressure and the decrease in the amount of air (and therefore heat) that can be held at higher elevations.
(iii) Distance from large bodies of water: The proximity of a location to large bodies of water can affect its climate. Locations near large bodies of water tend to have more moderate temperatures and more consistent precipitation patterns, due to the influence of the water on the local climate.
(iv) Prevailing winds: The direction and strength of the prevailing winds can also affect a location’s climate. For example, locations downwind of large bodies of water may experience more rainfall, while locations downwind of deserts may be drier.
(i) Rain: is the most common form of precipitation, and it occurs when liquid water droplets fall from the clouds and reach the ground.
(ii) Snow: is a form of precipitation that consists of frozen water droplets that fall from the clouds and accumulate on the ground.
(iii) Sleet is a form of precipitation that consists of small, ice pellets that fall from the sky.
(iv) Hail is a form of precipitation that consists of balls or lumps of ice that fall from the sky.
Denudation is the process by which the surface of the earth is worn away by natural forces such as weathering, erosion, and transport.
(i) Climate: The climate in a given area can play a significant role in the rate of denudation. For example, areas with high levels of rainfall may experience faster rates of denudation due to the action of water on the earth’s surface.
(ii) Topography: The topography of an area, or its shape and elevation, can also affect the rate of denudation. For instance, steep slopes are more susceptible to erosion than gentle slopes, and higher elevations are more likely to experience erosion due to the action of wind and water.
A solution of ammonia is basic, hence it turns red litmes blue.
A catalyst, concentrated tetraoxosulphate(vi) acid must be used to speed up the reaction.
CaC₂(s) + H₂0(l) —> C₂H₂(g) + CaO(s)
It is used in the production of oxy-acetylene flame used for welding.
(iii) Saturation level.
(i) Rusting requires moisture but burning does not.
(ii) Burning requires heat while rusting does not.
The K₂Cr₂O7 is reduced.
Hydrogen gas is geven off with the formation of iron(11) Chloride (green).