Question

What is the increase in entropy when 11.2 l of o2 are mixed with 11.2 l of h2 at stp?

Answer 1

"When you add energy to the solid then it becomes a liquid.

STP is the temperature of 273.15 K (0 °C, 32 °F) which is absolute pressure based on  105 Pa (100 kPa, 1 bar).

S = 8.314 x 2.303 (v1 log.n1 + v2 log.n2)

= 8.314 x 2.303 (0.5 log 0.5+0.5 log 0.5)

= 8.314 x 2.303 (-0.3010)

=- 5.76