Chemistry, 13.02.2020 20:53 camcollins00

What is the total energy change for the following reaction: 2H2 + O2 -> 2H2O?

Given:
H-H bond: 436 kJ/mol
O-O double bond: 499 kJ/mol
H-O bond: 463 kJ/mol

A. -481 kJ/mol
B. + 445 kJ/mol
C. +63 kJ/mol
D. -730.5 kJ/mol

Answers: 2

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Answer from: natpiink

From the options provided the total energy change for the reaction :

$2H_{2} + O_{2} -- 2H_{2}O$ = ( A ) ; - 481 kJ/mol

The Total energy change ( Δ ) in a reaction is calculated as difference in energies between the reactants and products i.e. $D_{reactants} - D_{product}$

Reactants Energy

= 2 * ( 436 kJ/mol ) + 1 * ( 499 kJ/mol )

= ( 872 + 499 ) kJ/mol = 1371 kJ/mol

Product energy

= 4 * ( 463 ) kJ/mol

= 1852 kJ/mol

Hence Total energy ( $D_{reactants} - D_{product}$ )

= ( 1371 - 1852 ) kJ/mol

= -481 kJ/mol

Also from the results obtained we can conclude that the reaction is an endothermic reaction

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Answer from: kfcnkfnmnfk9513

$\large \boxed{\text{A. -481 kJ/mol}}$

Explanation:

You calculate the energy required to break all the bonds in the reactants.

Then you subtract the energy needed to break all the bonds in the products.

2H₂ + O₂ ⟶ 2H₂O

Bonds: 2H-H 1O=O 4O-H

D/kJ·mol⁻¹: 436 499 463

$\begin{array}{rcl}\Delta H & = & \sum{D_{\text{reactants}}} - \sum{D_{\text{products}}}\\\sum{D_{\text{reactants}}} & = & 2 \times 436 + 1 \times 499\\&=& 872 + 489\\&=&\text{1371 kJ}\\\sum{D_{\text{products}}} & = & 4 \times 463\\ &=& \text{1852 kJ}\\\Delta H &=& 1371 - 1852\\&=&\textbf{-481 kJ} \\ \end{array}\\\text{The total energy change is $\large \boxed{\textbf{-481 kJ/mol}}$}.$

What is the total energy change for the following reaction: 2H2 + O2 -> 2H2O? Given: H-H bond:

Answer from: Quest

Dissociation then hydration dissolving
•hydration •dissociation •dissolving which one goes to which

Answer from: Quest

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

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What is the total energy change for the following reaction: 2H2 + O2 -> 2H2O?

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