Chemistry, 30.07.2019 01:10 justinbailey96

The standard enthalpy of formation, δh°f, of hi(g) is +26 kj mol-1. which of the following is the approximate mass of hi(g) that must decompose into h2(g) and i2(s) to release 500. kj of energy?

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Answer from: naruto63

The mass of HI that must decompose to release the given amount of energy is 2459.72 g.

Explanation:

We are given:

$\Delta H^o_f_{HI}=+26kJ/mol$

So, for decomposition of hydrogen iodide, the enthalpy will be -26 kJ/mol

The chemical equation for the decomposition of HI into hydrogen and iodine follows:

$HI(g)\rightarrow \frac{1}{2}H_2(g)+\frac{1}{2}I_2(g);\Delta H^o=-26kJ/mol$

By Stoichiometry of the reaction:

26 kJ of energy is released when 1 mole of hydrogen iodide is decomposed.

So, 500 kJ of energy will be released when = $\frac{1}{26}\times 500=19.23mol$ of hydrogen iodide will be decomposed.

To calculate the mass of hydrogen iodide, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of HI = 19.23 mol

Molar mass of HI = 127.911 g/mol

Putting values in above equation, we get:

$19.23mol=\frac{\text{Mass of HI}}{127.911g/mol}\\\\\text{Mass of HI}=2459.72g$

Hence, the mass of HI that must decompose to release the given amount of energy is 2459.72 g.

Answer from: Quest

water molecules stay close to each other through cohesion, the collective action of hydrogen bonds between water molecules. cohesion plants draw water upwards from the root through the stem's transport tubes (xylem) to the leaf. this transport occurs even in large trees and against gravity. transpiration, evaporation of water from plant leaves, creates a tension on water molecules being pulled up from the stem and roots.

water also has high (the attraction of one substance to another) properties because of its polar nature. adhesion of water molecules to plant cell walls counteract gravity while water is transported from roots to leaves.

water exhibits a very high surface tension when compared to other liquids. surface tension is a property of a liquid that holds the surface together and allows it to resist an external force. by capillary action, the water forms concave menisci inside the pores. the high surface tension of water pulls the concavity outwards, generating enough force to lift water from the roots to the leaves of plants.

thus, cohesion, along with adhesion and surface tension creates a capillary action that keeps water molecules interacting and moving through the plants out to the leaf cells.

therefore, option d) is the correct answer.

explanation:

Answer from: Quest

The answer will be c

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The standard enthalpy of formation, δh°f, of hi(g) is +26 kj mol-1. which of the following is the ap...

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