Jamb 2018 Flashcards
(24 cards)
A substance that is used as a ripening agent for fruits is
Ethene
Mention 2 sulphides that are insoluble in acidified solution
CuS and PBS
An element used in the production of matches is
Sulphur
A correct electrochemical series
Na Ca Mg Al Zn Fe Pb H Cu Hg Ag Au
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
Force of repulsion exist
the solubility of a gaseous substance dependent?
Temperature and pressure
The solubility of a gas decreases with an increase in temperature and a decrease in pressure.
The boiling of fat and aqueous caustic soda is referred to as
Saponification
Which of the following pairs of substances will react further with oxygen to form a higher oxide?
A. CO2 and H2 O B. NO and H2 O C. CO and CO2 D. SO2 and NO
D
Suitable reagents for the laboratory preparation of nitrogen are
NaNO2 and NH3Cl
List metals that do not react with carbon and hydrogen
The oxides of Potassium, Sodium, Calcium, and Magnesium are not reduced when they react with carbon and hydrogen
An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is
Zn
The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is
Na2SO3
When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;
Nitrogen and rare gases
The choice of method for extracting a metal from its ores depends on the
Position of the metal on the electrochemical series
The knowledge of half-life can be used to
A. Create an element
B. Detect an element
C. to combine elements
D. Irradiate an element
A
Aluminium does not react with either dilute or concentrated trioxonitrate (V) acid because
It forms an insoluble substance on its surface which renders it passive
What can replace hydrogen from water?
Metals above hydrogen in the activity series can displace or replace hydrogen present in water (H2
O) example of such metals are Ca, K, Na etc. But the metals below hydrogen in the activity series cannot replace hydrogen in the activity series example of such metals are Cu, Hg.
During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment
electrode, Cu and H migrate to the cathode while,SO4
and OH migrate to the anode.CU is then discharged preferentially at the cathode, acquiring two electrons and is deposited as metallic copper, while OH is discharged preferentially at the anode and deposited as gaseous oxygen, then the SO4
and H still in the solution react, thereby making d solution acidic and then changing the litmus paper red which is the test for acids.
The derivative of benzene that can be used in making explosives is
Toluene
The situation obtained when a perfect gas expands into a vacuum is
. ΔH is zero and T Δ S is positive
The alkanoic acid found in human sweat is
Propanoic acid
Which of the compounds is composed of Al, Si, O and H?
Clay
Which of the following separation techniques can be employed in obtaining solvent from its solution?
A. Evaporation
B. Distillation
C. Filtration
D. Precipitation
B
In the upper atmosphere, the ultra-violet light breaks off a free chlorine atom from chlorofluorocarbon molecule. The effect of this is that the free chlorine atom will
Be very reactive and attack the ozone
