In a commercial chemical cold pack, an inner pouch containing water is broken and the water is allowed to mix with a sample of solid ammonium nitrate. the signs of the values for δh and δs for the dissociation reaction must be, respectivelypositive, negativepositive, positivenegative, positivenegative, negative

Positive, positive

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

is positive when randomness increases and is negative when randomness decreases.

Exothermic reactions are defined as the reactions in which energy is released in the form of heat and for the reaction comes out to be negative.

Endothermic reactions are defined as the reactions in which energy is absorbed in the form of heat and for the reaction comes out to be positive.

For a cold pack, the energy has to be absorbed for the dissolution of ammonium nitrate in water so that the surroundings feel cold.Thus as energy is absorbed, for the reaction comes out to be positive.

The solid form of ammonium nitrate is getting converted to ions and thus entropy increases and thus for the reaction comes out to be positive.

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