OAU POST UTME PRACTICE: Chemistry Quiz

In which of the following devices is nuclear fission applicable?
I. Atomic pile
II. Cathode ray tube
III. Hydrogen bomb
IV. Atomic bomb
V. Geiger Muller counter

The energy required to remove the most loosely bound electron from a gaseous atom to form a gaseous ion is

If a mixture of 1.25 moles of nitrogen gas, 2.0 moles of oxygen gas and an unspecified amount of hydrogen gas sealed in a vessel at 25°C exerts a pressure of 9.6Nm? and the partial pressure of hydrogen is 2.35Nm-2, calculate the mass of hydrogen gas in the
mixture. (H = 1)

Arrange the following gases in increasing order of diffusion rate: i. Helium ii. Methane iii. Nitrogen iv. Hydrogen sulphide

The ions X- and Y+ are isoelectronic, each containing a total of 10 electrons. How many protons are in the nuclei of the neutral atoms of X and Y respectively

For the reaction A + B → C. The rate is given as R = k[A]*[B]’ when the concentration of the reaction remains the same but when the concentration of B is doubled and that of A is constant, the rate quadruples.
The values of * and ‘ are respectively

What is the temperature at which the reaction below is at equilibrium?

The sample of a radioactive element with a half life of 6hrs has an initial mass of 250g. Calculate the time it will take for the mass of the sample to remain 20g

Which of the following are reasons why reaction rates increase as temperature increases?
I. Collisions are more frequent between molecules at higher temperatures.
II. A greater fraction of collisions have sufficient energy to exceed Ea at higher temperatures.
III. Reactant concentrations are higher at higher temperatures.

The solubility of calcium fluoride at 37°C is 3.9 gdm-3. What is the solubility product of the salt at this temperature? [Ca=40.0, F=19.0 gmol-1]

Consider the following chemical equations
Which of the numbered chemical species react like Lewis acid?

When ammonium nitrate is dissolved in water

A substance X can conduct electricity when in molten form but not when in solid form. X could be

Which of the following oxides share a similar chemical property with oxygen?

What is the standard cell potential for the reaction
2Cr + 3Sn2+ → 3Sn + 2Cr3+, given the E° values
shown
Cr3+ + 3e- → Cr, E° = -0.744V
Sn2+, + 2e- →Sn, E°= -0.141V

Calcium carbonate, CaCO, decomposes upon heating to calcium oxide and carbon dioxide.
What mass of solid calcium carbonate is required to produce 2.40 dm3 of carbon dioxide measured at STP? (GMV =22.4 dm3)

Consider the table below
Which of the options below identify method of preparation of i, ili and iv?

An element X, consisting of two isotopes of. mass numbers 35 and 37, has an atomic number 35.5. What is the relative abundance of the isotope of mass number 37

An aqueous solution of a substance turns acidification K2CrO, solution from orange to green. The aqueous solution also decolourises acidified KMn solution. It can therefore be inferred that the substance in the aqueous solution is

A choloform solution of a compound was spotted at a distance of 0.5cm from the base of a 10cm long chromatopaper. Upon dilution, the solvent front got to a place 0.25cm from the top of the chromatopaper. If the R, value of the compound is 0.72, what is the distance moved by the spot of the compound way up from the origin

The relative rate of diffusion of a gas as compared with sulphur (VI) oxide is V5,:2, then the relative molecular mass of the gas is?
[S=32, 0=16]

For the reaction
2H2(g) + 2NO(g) → N2(g) + 2H20(g)
the rate law is rate = k[H2)(NOJ2.
At a given temperature, what is the effect on the reaction rate if the concentration of H2 is doubled and the concentration of NO is halved?