Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
A mixture of iron and sulphur can be separated by dissolving the mixture in?
steam
dilute hydrochloric acid
dilute sodium hydroxide
benzene
Correct answer is D
No explanation has been provided for this answer.
The addition of water to calcium oxide leads to?
a physical change
a chemical change
the formation of a mixture
an endothermic change
Correct answer is B
No explanation has been provided for this answer.
88.71 KJ
85.48 KJ
-204.00 KJ
-3427.40 KJ
Correct answer is D
∆G = ∆H - T∆S; T = 2s° + 273 = 298 k
∆G = 89 - 298 x 11.8 = -3427.4
HCOOH
C2H5COOH
CH3COOH
C3H7COOH
Correct answer is C
Conc. of KOH = 39 x 0.02 = 0.78 g/dm3
25cm3 require 0.03 g of CnH2n + 1 COOH 1000CM3 → x x = (1000) / (25) x 0.03 = 1.2g
CnH2n + 1COOH + KOH → CnH2n + 1 COOK + H2O
from (MAVA) / (MB x VB) = (1) / (1) (MA x 1.2) / (0.02 x 0.78) = (1) / (1)
MA = 0.013
Con. = Molarity x Molecular Mass
Molecular Mass = (0.78) / (0.013) x 60
CnH2n + 1 COOH = 60
12n + 1 (2n + 1) + 12 + 32 + 1 = 6
14n = 60 - 46; n = (14) / (14) = 1
∴ CH3COOH
The synthetic detergents are preferred to soap for laundry using hard water because?
detergents are water soluble while soap is not
the calcium salts of detergents are water soluble
the magnesium salt of soap is soluble in hard water
soap does not have a hydrocarbon terminal chain
Correct answer is B
No explanation has been provided for this answer.