The highest rate of production of carbon (lV) oxide can be achieved using
0.05 mol -3HCI and 5g powdered CaCO3
0.05 mol -3HCI and 5g lump CaCO3
0.10 mol -3HCI and 5g powdered CaCO3
0.025 mol -3HCI and 5g powdered CaCO3
Correct answer is C
No explanation has been provided for this answer.
An increase in entropy can best be illustrated by
mixing of gases
freezing of water
the condensation of vapour
solidifying candle wax
Correct answer is A
No explanation has been provided for this answer.
+ 262 KJ mol -1
- 262 KJ mol -1
+ 42 KJ mol -1
- 42 KJ mol -1
Correct answer is D
\(\Delta H (formation) (CO_2) = -394\)
\(\Delta H (formation) (H_2 O) = -242\)
\(\Delta H (formation) (CO) = -110\)
\(X = \sum H_{P} ^{F} - \sum H_{R} ^{F}\)
= (-394+ 0) - (-110 - 242 )
= -394 +352
= - 42 kJmol\(^{-1}\)
A metal M displaces zinc from ZnCl solution
This shows that
electrons flow from zinc to M
M is more electropositive than zinc
M is more electonegative than zinc
zinc is more electropositive than M
Correct answer is B
No explanation has been provided for this answer.
What number of moles of Cu 2+ will be deposited by 360 coulombs of electricity?
[f = 96500 C mol -1]
5.36 x 10 -4 mole
1. 87 x 10 10 -3 mole
9. 35 x 10 -4 mole
3. 73 x 10 -3
Correct answer is B
Cu\(^{2+}\) + 2e\(^{-}\)\(_{(aq)}\) \(\rightarrow\) Cu\(_{(s)}\)
Liberating 1 mole of Cu
2 x 1F = 2 x 96,500C = 193,000C of electricity is needed
Hence, 193,000C = 1 mole
360C of electricity = \(\frac{360C \times 1 mol}{193,000C}\)
= 0.001865 mol
= 1.87 x 10\(^{-3}\) moles