Which of the following would react most rapidly?
a)powdered zn in 1.0 m hcl at 25°c
b)powdered zn in 2.0 m hcl at 40°c
c)a lump of zn in 2.0 m hcl at 25°c
d)a lump of zn in 1.0 m hcl at 40°c

b)powdered Zn in 2.0 M HCl at 40°C

Explanation:

The rate of reaction increases with increase in temperature, increase in concentration of the reactant and increase in surface area. Powered Zn has a greater surface area than a lump of Zn. Also 40°C is a higher temperature than 25°C. Furthermore, 2 M HCl is a more concentrated acid than 1 M HCl. Considering the above three factors powdered Zn in 2.0 M HCl at 40°C will react the fastest.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa