A)In a chemical reaction two gases combine to form a solid. What do you expect for the sign of ΔS?

B) For which of the following processes does the entropy of the system increase? (Select all that apply.)

-> alignment of iron filings in a magnetic field

-> the melting of ice cubes at 10°C and 1 atm pressure

-> the dissolution of HCl(g) in water to form concentrated hydrochloric acid

-> the reaction of hydrogen gas with oxygen gas to form water vapor

->separating a mixture of N2 and O2 into two separate samples, one that is pure N2 and one that is pure O2

A)In a chemical reaction two gases combine to form a solid. What do you expect for the sign of ΔS?

S is higher in gases than solids

B) For which of the following processes does the entropy of the system increase? (Select all that apply.)

-> alignment of iron filings in a magnetic field
S is higher before alignment

-> the melting of ice cubes at 10°C and 1 atm pressure
S is higher in liquids than in solids

-> the dissolution of HCl(g) in water to form concentrated hydrochloric acid
S is higher in gases than in liquids

-> the reaction of hydrogen gas with oxygen gas to form water vapor
S is higher in gases than in liquids.
->separating a mixture of N2 and O2 into two separate samples, one that is pure N2 and one that is pure O2

dS increases if pure N2 and pure O2 are mixed.

thanx!!

A) In a chemical reaction where two gases combine to form a solid, you would expect the sign of ΔS (change in entropy) to be negative. This is because gases generally have higher entropy than solids, so when gases are converted to a solid, there is a decrease in the overall entropy of the system.

To understand this concept, you can think about the behavior of particles in a gas compared to a solid. In a gas, particles have more freedom of movement and can occupy a larger volume, resulting in greater disorder and higher entropy. On the other hand, in a solid, particles are tightly packed and have limited movement, leading to lower entropy.

B) The processes in which the entropy of the system increases are:

1) Alignment of iron filings in a magnetic field: When iron filings are placed in a magnetic field, they align themselves along the field lines. This alignment increases the orderliness of particles, leading to an increase in entropy.

2) The dissolution of HCl(g) in water to form concentrated hydrochloric acid: When HCl(g) dissolves in water, the individual HCl molecules disperse throughout the water, increasing the disorder of the system and thus increasing entropy.

3) The reaction of hydrogen gas with oxygen gas to form water vapor: The reactants (hydrogen gas and oxygen gas) have higher entropy due to their random orientation and motion. However, when they combine to form water vapor, the number of particles increases, leading to a net increase in entropy.

4) Separating a mixture of N2 and O2 into two separate samples, one that is pure N2 and one that is pure O2: Initially, the mixture of N2 and O2 has a certain level of disorder and randomness. By separating them into two separate samples, the disorder decreases, resulting in an increase in entropy.

On the other hand, the melting of ice cubes at 10°C and 1 atm pressure does not result in an increase in entropy. The transition from a solid (ice) to a liquid (water) does not significantly change the disorder or randomness of the particles, so the entropy remains relatively constant in this process.

A,E INCREASES

B,C,D DECREASES