How is enthalpy used to predict whether a reaction is endothermic or exothermic?

Chemistry

2 answers:

lana [24]4 years ago

5 0

The correct option is this: WHEN THE ENTHALPY CHANGE OF THE REACTION IS POSITIVE, THE REACTION IS ENDOTHERMIC.
All chemical reactions are divided into two classes, these are exothermic and endothermic reaction. An exothermic reaction is a type of reaction in which energy is lost to the environment, thus the enthalpy change of the reaction is negative. An endothermic reaction is a type of reaction in which energy is absorbed from the environment, thus the enthaply change of the reaction is positive.

UkoKoshka [18]4 years ago

5 0

Answer: When the enthalpy change of the reaction is positive, the reaction is endothermic.

Explanation: Exothermic reactions are defined as the reactions in which energy of the product is less than the energy of the reactants. The total energy is released in the form of heat and $\Delta H$ for the reaction comes out to be negative.

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and $\Delta H$ for the reaction comes out to be positive.

$\Delta H=H_{products}-H_{reactants}$

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Which best explains why the trend in noble gas boiling points increases down the group?A) increasing dispersion interactions B)

zhenek [66]

Answer:

A) increasing dispersion interactions

Explanation:

Polarizability allows gases containing atoms or nonpolar molecules (for example, to condense. In these gases, the most important kind of interaction produces dispersion forces, attractive forces that arise as a result of temporary dipoles induced in atoms or molecules.

Dispersion forces, which are also called London forces, usually increase with molar mass because molecules with larger molar mass tend to have more electrons, and dispersion forces increase in strength with the number of electrons. Furthermore, larger molar mass often means a bigger atom whose electron distribution is more easily disturbed because the outer electrons are less tightly held by the nuclei.

Because the noble gases are all nonpolar molecules, the only attractive intermolecular forces present are the dispersion forces.