When is heat negative

The larger the K value, the more the reaction will tend toward the right and thus to completion. Suppose that the following reaction is at equilibrium and that the concentration of N 2 is 2 M, the concentration of H 2 is 4 M, and the concentration of NH 3 is 3 M. What is the value of K c? For the previous equation, does the equilibrium favor the products or the reactants?

Is this an exothermic or endothermic reaction? Because the K value decreases with an increase in temperature, the reaction is an exothermic reaction. In the initial reaction, the energy given off is negative and thus the reaction is exothermic. However, an increase in temperature allows the system to absorb energy and thus favor an endothermic reaction; the equilibrium will shift to the left. If K c increases with an increase in temperature, the reaction to shifts to the right.

If K c increases with a decreases in temperature, the reaction to shifts to the right. If K c decreases with a decrease in temperature, the reaction to shifts to the left. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry.

It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search. If an object with mass bla and specific heat bla is placed into a bla g calorimeter with an initial temperature of bla and a specific heat of bla, and the temperature of the calorimeter rises to bla at the end of the experiment, how much heat was lost by the object?

Wouldn't this response to the above question mean that the object gained heat? Your assumptions are correct , and from the wording of the question, the "correct" answer doesn't make sense, unless like you said, the object gained heat, which is possible; people have negative profits all the time. Sign conventions are not flawed in chemistry, but you just have to be careful when wording a question.

To answer the title of your question, yes it is not only customary, it is necessary to express heat loss as a negative number, but the question still has to be phrased correctly--using the term "lost" serves as a negation in this use of language, the same way the unary operator in -1 serves as negation for a number.

If heat loss were not expressed negatively, it wouldn't make sense because the system of an exothermic reaction must lose energy for its surroundings to gain it. Sign up to join this community.

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Create a free Team What is Teams? Learn more. Is it customary to express heat loss as a negative number? Ask Question. Asked 8 years ago. Active 8 years ago. Viewed 9k times. Improve this question.