Copper can best be purified by
roasting the impure copper in a blast furnace
heating the oxide with coke
electrolyzing a copper (ll) salt solution using the impure copper as the anode
converting the impure copper to a trioxonitrate (V)
washing the impure copper with sodium hydroxide solution
Correct answer is C
No explanation has been provided for this answer.
Which of the following carbohydrates does NOT usually occur in the crystalline form?
Fructose
Glucose
Sucrose
Maltose
Cellulose
Correct answer is E
No explanation has been provided for this answer.
isotopy
isomerism
allotropy
hygroscopy
sublimation
Correct answer is C
No explanation has been provided for this answer.
- 108Kj
-54 kj
-27 kj
+27 kj
+54 kj
Correct answer is A
Given that \(KOH_{(aq)} + HCl_{(aq)} \to KCl_{(aq)} + H_{2}O_{(l)} ; \Delta H = -54 kJ/mol\)
The standard heat of neutralization is the amount of heat evolved when 1 mole of hydrogen ion from an acid reacts with 1 mole of hydroxide ion from the base to form one mole of water, under standard conditions.
\(\therefore 2NaOH_{(aq)} + H_{2}SO_{4(aq)} \to Na_{2}SO_{4(aq)} + 2H_{2}O_{(l)} ; \Delta H = -(2 \times 54 kjmol^{-1})\)
\(\therefore \Delta H = -108 kJmol^{-1}\)
Which of the following gases will bleach moist litmus paper?
CI2
CO2
SO2
HCI2
N2 O
Correct answer is A
No explanation has been provided for this answer.