A solid precipitates from a solution, releasing heat as it does so.
a) yes
b) no

b) no

Explanation:

To determine if the change will be spontaneous in the given description.

When a solid precipitate from a solution, the liquid has been converted to solid. For this to happen, the application of heat energy occurs in that state. As a result, the reaction will be exothermic. In an exothermic reaction, heat is lost from the system. Thus Δ H is usually negative.

This state's entropy will also be negative since entropy measures the degree of disorder of a system.

ΔS = -ve

Let's recall that for a reaction to being spontaneous, ΔG must be negative and ΔG can be expressed by the equation ;

ΔG = ΔH - TΔS

ΔG = -ve - (+ve)×(-ve)

ΔG = -ve(2)

So since the negative is larger, we can determine that the reaction will not be spontaneous.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

answer; natural resources;