Which reactions are spontaneous?

i. c2h5oh(l) + 3o2(g) 2co2(g) + 3h2o(l), g = –36.7 kj
ii. 2c6h6(l) + 15o2(g) 12co2(g) + 6h2o(l), g = –6,405 kj
iii. caco3(s) cao(s) + co2(g), g = 13.0 kj
iv. ni(s) + cl2(g) nicl2(s), g = 1,130.28 kj
a.) i and ii
b.) iii and iv
c.) i and iii
d.) ii and iv

The correct answer is option A.

Explanation:

Gibbs's free energy is defined as the energy which is associated to the chemical reaction that can be used to do work. It is represented as "G".

When Gibbs's free energy is negative, the reaction is said to be spontaneous and when Gibbs's free energy is positive, the reaction is said to be non-spontaneous.

From the given options:

Reaction 1 and reaction 2 has negative Gibbs's free energy and hence, is considered as the spontaneous reactions.

Reaction 3 and reaction 4 has positive Gibbs's free energy and hence, is considered as the non-spontaneous reactions.

Therefore, the correct answer is Option A.

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :