4.0 g of sodium hydroxide in 250 cm3 of solution contains?
- A. 0.40 moles per dm3
- B. 0.10 moles per dm3
- C. 0.04 moles per dm3
- D. 0.02 moles per dm3
NH3 + H3O+
→ NH4+ + H2O. It may be deduced from the reaction above that?
- A. a redox reaction has occurred
- B. H3O+ acts as an oxidizing agent
- C. H3O+ acts as an acid
- D. water acts as an acid
A student prepares 0.5 M solution each of hydrochloric and ethanoic acids and then measured pH. The result would show that the?
- A. pH values are equal
- B. HCI solution has a higher pH
- C. sum of the values is 14
- D. ethanoic acid solution has a higher pH
The phenomenon whereby sodium trioxocarbonate (IV) decahydrate loses some of its water of crystallization on exposure to the atmosphere is known as?
- A. deliquescene
- B. hygroscopy
- C. effervescence
- D. efflorescence
Water can be identified by the use of?
- A. anhydrous copper (II) tetraoxosulphate (VI)
- B. anhydrous sodium trioxocarbonate (IV)
- C. potassium heptaoxochromate (VII)
- D. copper (II) trioxocaronate (IV)
The air around a petroleum refinery is most likely to contain?
- A. CO2, SO3 and N2O
- B. CO2, CO and N2O
- C. SO2, CO and NO2
- D. PH3 H2O and CO2
Argon is used in gas-filled electric lamp because it helps to?
- A. prevent the reduction of the lamp fillaments
- B. prevent oxidation of the lamp fillaments
- C. make the lamp fillament glow brightly
- D. keep the atmosphere in the lamp inert
Water has a rather high boiling point despite its low molecular mass because of the presence of?
- A. hydrogen bonding
- B. covalent bonding
- C. ionic bonding
- D. metallic bonding
Which group of elements forms hydrides that are pyramidal in structure?
- A. III
- B. IV
- C. V
- D. VI
As the difference in electronegativity between bonded atoms increases, polarity of the bond?
- A. decreases
- B. increases
- C. remains unchanged
- D. reduces to zero
Two atoms represented as U and U are?
- A. isomers
- B. allotropes
- C. isotopes
- D. anomers
An element, E, has the electronic configuration 1s22s22p63s2p3. The reaction of E with a halogen X can give?
- A. EX3 and EX5
- B. EX3 only
- C. EX5 only
- D. EX2 and EX3
For iodine crystals to sublime on heating, the molecules must acquire energy that is?
- A. less than the forces odf attraction in the solid
- B. equal to the forces of attraction in th solid
- C. necessary to melt the solid
- D. greater than the forces of attraction in both the solid and the liquid phases
How many moles of oxygen molecules would be produced from the decomposition of 2.50 moles of potassium trioxochlorate (V)?
- A. 2.50
- B. 3.50
- C. 3.75
- D. 7.50
A balanced chemical equation obeys the law of?
- A. conservation of mass
- B. difinite proportions
- C. multiple proportions
- D. conservation of energy
Which of the following substances is a mixture?
- A. Sulphur powder
- B. Bronze
- C. Distilled water
- D. Ethanol
An example of a polysaccharides is?
- A. —dextrose
- B. mannose
- C. glucose
- D. starch
Alkanals can be differentiated from alkanones by reaction with?
- A. 2,4-dinitrophenylhydrazine
- B. hydrogen cyanide
- C. sodium hydrogen sulphite
- D. Tollen's reagent
The characteristics reaction of carbonyl compounds is?
- A. substitution
- B. elimination
- C. addition
- D. saponfication
An organic compound containing 40.1% carbon and 6.6% hydrogen has an empirical formula of?
- A. C2H4O2
- B. C2H3O2
- C. CH2O
- D. CH3O
The functional group present in an organic compound which gives bubbles on treatment with a saturated solution of NaHCO3 is?
- A. hydroxyl group
- B. carboalkoxyl group
- C. carbonyl group
- D. carboxyl group