Which of the following is a condition for a spontaneous reaction?
∆H -T is zero
∆H-T∆ S is positive
∆H-T∆ S is negative
∆S is zero
∆S is positive
Correct answer is C
No explanation has been provided for this answer.
x belongs to group 1, Y belongs to period 2,
x belongs to group 1, Y belongs to period 4
x belongs to group 2, Y belongs to period 1
x belongs to group 3, Y belongs to period 2
x belongs to group 3, Y belongs to period 4
Correct answer is B
No explanation has been provided for this answer.
Which of the following statements is not true of tin? it
is a p-block element
is extracted from cassiterite SnO 2
is used for protecting iron containers from corrosion
combines with copper to form the alloy brass
shows two oxidation states, + 2 and + 4 in most of its compounds
Correct answer is D
No explanation has been provided for this answer.
-46KJ mol -1
-184KJmol -1
-92KJmol -1
184KJmol -1
+46KJmol -1
Correct answer is A
In the reaction the enthalpy of formation 2 mole of NH3 is - 92kJ. Therefore the standard \(\Delta H\) of formation = \(\frac{-92kJ}{2} = -46KJmol^{-1}\).
Which of the following parts is common to both the disc and mouldboard plough?
Ploughshare
Landslide
Coulter
Beam
Correct answer is D
No explanation has been provided for this answer.