Molar mass:
Atomic mass O = 16.0 a.m.u
O₃ = 16.0 x 3 => 48.0 g/mol
Therefore:
1 mole O₃ --------------- 48.0 g
0.020 mole O₃ ---------- ??
0.020 x 48.0 / 1 =
0.96 / 1 => 0.96 g
hope this helps!
Answer : The correct option is C.
Explanation :
Enthalpy of reaction : It is defined as the changes in heat energy takes place when reactants go to products. It is denotes as 
.
= Energy of product - Energy of reactant
is positive when heat is absorbed and the reaction is endothermic.
is negative when heat is released and the reaction is exothermic.
In the given potential energy diagram, the energy of product at higher level and energy of reactant at lower level. The for this reaction will be positive.
So, the enthalpy of reaction is defined as the difference of the energy of the reactants and the energy of the products.
According to half life equation:
T(1/2) = ㏑2 / K1
when the T(1/2) = 4 min * 60 = 240 sec
by substitution:
240 = 0.6931 / K1
K1 = 2.9 x 10^-3
when the second T(1/2) = 20 sec, so to get K2:
T(1/2) = 0.6931 / K2
by substitution:
20 = 0.6931 / K2
∴K2 = 3.4 x 10^-2
so, we can get T2 by using this formula:
㏑ (K2/K1) = Ea/R (1/T1 - 1/T2)
by substitution:
㏑(3.4 x 10^-2)/(2.9 x 10^-3) = (24520 / 8.314) (1/298 - 1/T2)
∴ T2 = 396.7 K
= 396.7 - 273 = 123.7 °C
