For the reaction, 2 A g + B g → 2 D g ; ∆ U ∘ = - 10 . 5 kJ and ∆ S ∘ = - 44 . 1 J K - 1 . Calculate ∆ G ∘ for the reaction and predict whether the reaction may occur spontaneously. ( R = 8 . 314 × 10 - 3 kJ K - 1 mol - 1 , T = 298 K ).

For the reaction, 2 A g + B g → 2 D g ; ∆ U ∘ = - 10 . 5 kJ and ∆ S ∘ = - 44 . 1 J K - 1 . ( R = 8 . 314 × 10 - 3 kJ K - 1 mol - 1 , T = 298 K ). ∆ H ∘ = ∆ U ∘ + RT ∆ n = - 10 . 5 + 8 . 314 × 10 - 3 × 298 × - 1 = - 12 . 978 kJ mol - 1 ∆ G ∘ = ∆ H ∘ - T ∆ S ∘ ∆ G ∘ = - 12 . 978 - 298 × - 44 . 1 × 10 - 3 = 0 . 1638 kJ mol - 1 = 163 . 8 J mol - 1 . Since, the value of ∆ G ∘ is positive, the reaction is non-spontaneous.

Loam is soil composed mostly of sand (particle size > 63 micrometres), silt (particle size 2 ), and a smaller amount of clay (particle size < 2 ). By weight, its mineral composition is about 40 - 40 - 20 % concentration of sand–silt–clay, respectively. These proportions can vary to a degree, however, and result in different types of loam soils: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, and loam. Loam is considered ideal for gardening and agricultural uses because it retains nutrients well and retains water while still allowing excess water to drain away.