Naturally occurring lithium consists of 90% \( ^7_3Li \text{ and 10% } ^6_3 Li. \) What is the relative atomic mass of lithium?
- A. 6
- B. 6.8
- C. 6.9
- D. 7
- E. 7.1
Why does the treatment of cotton fabrics with dilute acids weaken the materials?
- A. Cotton is hydrolysed completely to glucose
- B. The fabrics are soluble in dilute acids
- C. The molecular chains are partially broken
- D. The molecular chain length f the fabric increases
- E. The thread holding the fabric together Is completely destroyed.
An organic compound gave the following results on analysis: C = 29.3% ; H = 5.7%; Br = 65%.
What is the empirical formula of the compound? [C = 12, H = 1, Br=80]
- A. CH3Br
- B. C2H5Br
- C. C3H5Br
- D. C3H7Br
- E. C4H9Br
What mass of copper is deposited when 6.5g of granulated zinc reacts with excess copper(II) tetraoxosulphate(VI) solution?
The equation for the reaction is: Zn(s) + \( CuSO_4(aq)→ ZnSO_4(aq)+ Cu(s)\)[CU= 64; Zn=65]
- A. 3.2 g
- B. 3.25 g
- C. 6.4 g
- D. 6.5 g
- E. 64.0 g
Which element is the most electronegative?
- A. calcium
- B. fluorine
- C. iodine
- D. oxygen
- E. sodium
What change will occur to the equilibrium mixture
\( 2CrO^{2-}_4(aq) + 2H^+(aq) ⇔ Cr_2O^{2-}_7(aq) + H_2O(l) \) when excess sodium hydrogen solution is added?
- A. A yellow precipitate of Cr(OH)3 is formed
- B. An orange precipitate of Cr(OH)3 is formed
- C. The colour changes from orange to yellow
- D. The colour changes from yellow to orange
- E. There is no visible reaction.
What is the IUPAC name of CH3CCI=C(CH3)2?
- A. 2-chloro -3 methylbut -2yne
- B. 2 -chloro -3 methylbut -2ene
- C. 2 -chloro -3 methylbutene
- D. 3- methyl -2-chlorobut -2-ene
- E. 3- methyl -2. chlorobut -2 yne
Which formula is used to indicate the degree of acidity of an acid?
- A. \( [H^+] = ^{\text{mass of acid relative}} molecular mass of acid \)
- B. F = number of H+ = ions x molar mass of the acid
- C. Kw = [H+][OH-]
- D. pH = - log10[H+]
- E. pKa = -log10Ka
Which compound will give propane when it Is dehy drated by an excess of hot, concentrated tetraoxosvlphate(VI) acid?
- A. CH3CH2CHO
- B. CH3CH2CH2OH
- C. CH3CH2COQH
- D. CH3CH20CH
- E. CH3CH3OH
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 → 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.