Solid potassium hydroxide may be used to unclog sink drains. the dissolution of potassium hydroxide in water is quite exothermic. what are the signs of δhsys and qsurr?

Answer is: The sign of ΔHsys is - and the sign of qsurr is +.

First Law of Thermodynamics - any heat lost by the system must be absorbed by the surroundings.

-qsystem = qsurroundings.

There are two types of reaction:

1) exothermic reaction (chemical reaction that releases more energy than it absorbs).  

For example, ΔH(reaction) = -225 kJ/mol; this is exothermic reaction.

2) endothermic reaction (chemical reaction that absorbs more energy than it releases).

the answer is a. co2, this would be colder than the : )

explanation:

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.