A calcium atom and a calcium ion have the same
- A. chemical properties
- B. electric charge
- C. electronic structure
- D. number of electrons
- E. number of neutrons
Which is NOT a synthetic polymer?
- A. nylon
- B. Orion
- C. Perspex
- D. polystyrene
- E. wool
The reaction C2H6 β C2H + H2 is known as
- A. dehydration
- B. dehydrogenation
- C. displacement
- D. hydrogenation
- E. reduction
The boiling point of water is higher than the boiling point of ethanol because
- A. the bonding in water is electrovalent (ionic) whereas the bonding in ethanol is convalent
- B. the hydrogen bonding between water molecules is stronger than the hydrogen bonding between ethanol molecules
- C. water has a higher lattice energy than ethanol.
- D. water has hydrogen bonding between its molecules but ethanol has no hydrogen bonging between its molecules;
- E. water is a better solvent than ethanol.
B is an isotope of the element \(^{238} _{92}Ur\). The isotope B has
- A. 46 protons and 119 neutrons
- B. 92 protons and 92 neutrons
- C. 92 protons and 146 neutrons
- D. 92 protons and 238 neutrons
The number of hydrogen ions in 1.0dm\(^3\) of a 0.25 mole tetraoxosulphate(Vl) acid solution is
[Avogadro constant = 6.02 x 10\(^{23}\)]
- A. 1.45x1023
- B. 1.50 x l023
- C. 3.00x1023
- D. 3.15x1023
- E. 6.00x1023
Chlorine is used in water purification because it
- A. bleaches impurities in the water
- B. decolorizes water
- C. destroys bacteria
- D. is extremely soluble in water
- E. is pleasant tasting
Which statement is NOT true about the composition of starch?
- A. It contains only the atoms of carbon, hydrogen oxygen
- B. It is a polysaccharide
- C. Its empirical formula is C2H20.
- D. It is made from the monomerC6H12O6.
- E. The hydrogen and oxygen atoms are in the ratio 2:1.
Which compound is a component of baking powder?
- A. Na2CO3
- B. Na2SO4
- C. KH2CO3
- D. NaHCO3
- E. NaHSO4
if an element X with atomic number 13 combines with an element Y whose atomic number is 8 the most likely formula of the compound formed between X and Y is?
- A. XY
- B. X2Y
- C. XY2
- D. X3Y2
- E. X2Y3
When an electric current is passed through a solution containing dilute tetraoxosulphate (Vi) acid, 190 cm3 of hydrogen gas is evolved. if the measurements were made at 26Β°C and 736 mmHg, what is the volume of hydrogen at s.t.p.?
- A. 164 cm3
- B. 168 cm3
- C. 179.1.cm3
- D. 201.5cm3
- E. 546 cm3
A measure of the degree of disorderliness in a chemical system is known as the
- A. activation energy
- B. enthalpy
- C. entropy
- D. equilibrium
- E. free energy.
Fructose and glucose are
- A. allotropes of each other.
- B. both disaccharides
- C. dimere of each other.
- D. isomers of each other
- E. isotopes of each other
Detergents are better than soaps for washing in hard water because
- A. hard water contains insoluble calcium salts.
- B. they contain bleaching powder.
- C. they contain palmitic acid.
- D. they do not form insoluble calcium and magnesium salts.
- E. they are organic compounds.
Which method is NOT used to determine rate of a reaction?
- A. change in amount of precipitate formed
- B. change in equilibrium constant
- C. change in intensity of colour
- D. change in pH values.
- E. change in total gas pressure
Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?
- A. boiling off the ethanoic
- B. filtration
- C. fractional crystallisation
- D. fractional distillation
- E. isomerisation
To test for the presence of chloride ions in ion, correct sequence of reagents to use is
- A. Ba(NO3)2(aq) then HNO3(aq).
- B. HCl(aq) then Ba(NO3)2(aq).
- C. HCl(aq) then Ag3(aq).
- D. HNO3(aq) then fresh FeSO4(aq).
- E. HNO3(aq) then AgNO3(aq).
NaCl(s) does NOT conduct electricity, but N(aq) does. This is because
- A. NaCl(s) is non-ionic but NaCl(aq) is ion
- B. NaCl(aq) contains mobile electrons, where absent in NaCl(s).
- C. NaCl(aq) contains mobile ions which Nacl,) does not contain.
- D. NaCl(s) ionizes partiality while NaCl(aq) iodizes completely.
- E. NaCl(s) decomposes when heated but NCl(aq) is stable to heat. β
The green colour solution of an Fe2 salt changes to a brown solution of an Fe3+ salt by
- A. conversion.
- B. elimination.
- C. oxidation.
- D. reduction.
- E. substitution.
A gas X diffuse through porous partition at the rate of 3 cm3 per second. Under the same condition hydrogen diffused at the rate of 15 cm3 per second.
What is the 42. relative molecular mass of X.
- A. 5
- B. 12
- C. 18
- D. 45
- E. 50
Faraday s first law of electrolysis can be expressed mathematically as
- A. m=I/it
- B. mΞ±it
- C. Q=it
- D. QΞ±I/it
- E. QΞ±it