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if there is an increase in the number of gas molecules , then ^S > 0

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10y ago
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9y ago

Look up in a table the standard molar entropies of the reactants and the products. This is usually abbreviated at S0, and is in units of J/(mol*K)

Use Hess's Law, which states that the change in entropy of a reaction is equal to the sum of the standard entropies of the products (multiplied by the coefficients from the balanced equations) minus the sum of the standard entropies of the reactants (multiplied by the sum of the coefficients from the balanced reaction.

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15y ago

It depends on if you are calculating the amount of usable energy from a reaction or the change in enthalpy. To calculate the Change in enthalpy of a chemical reation: ΔHreaction= ΣΔHfO (Products) - ΣΔHfO (Reactants) Which is the sum of the standard enthalpy change of formations of the products (multiplied by their balanced coefficients) minus the sum of the standard enthalpy change of formations of the reactants (also multiplied by their balanced coefficients). This is to say, in the equation: aA + bB -> cC + dD ΔHreaction = [( c x ΔHfO C) + (d x ΔHfO D) ] - [( a x ΔHfO A) + (b x ΔHfO B) ] However, the amount of usable of a reaction is given by ΔGor the change in Gibb's free energy. Gibb's free energy is the change in enthalpy minus the change in entropy multiplied by the temperature: ΔG = ΔH - TΔS Where T is the temperature in kelvin and ΔS is the change in entropy.

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14y ago

delta H = mass * heat capacity * delta temperature

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12y ago

How does the entropy increase in a chemical reaction?

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6y ago

The change in enthalpy (∆H) is the enthalpy of the products - the enthalpy of the reactants. Under conditions of constant pressure, ∆H = q (heat).

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16y ago

the formula is, del S=RlnV2/V1

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Q: What explains the entropy change of a gas reaction?
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Continue Learning about Natural Sciences

What occurs in a reaction in which the reactant is a solid and the product is a gas?

the answer is D. AS most likely would be positive because a gas has a greater entropy than a solid.


Is Gas produced from a reaction is a phase change and not a chemical change.?

A gas released during a chemical reaction is a chemical change.


What changes a liquid or a solid to a gas?

usually a change in temperature.... OR PRESSURE Which all mean a change in entropy of the system


How does a change in phase affect entropy changes in a reaction?

It happens because, even in the same compound, atoms/molecules in different phases have different types of behaviour. For example, unlike solids, liquid and gas molecules can 'flow' around.


What in entropy?

If you increase the molecules, or go from a gas to a liquid or vice versa, entropy increases.

Related questions

What describes the entropy change of gas reaction?

if there is an increase in the number of gas molecules , then ^S > 0


Which of the following describes the entropy change of a gas reaction?

If there is an increase in the number of gas molecules, then S > 0.


How does entropy change in gas reactions?

Reactions that increase the moles of gas will increase in entropy.


Under what condition can entropy decrease in a system?

First of all, entropy is the defined as the extent to which something is disordered. In chemistry, for entropy in a SYSTEM to decrease, the products of a reaction must be less disordered than the reactants. The extent of "disordered-ness" can be seen by the physical states of the substances. A gas is more disordered than a liquid, which is more disordered than a solid. So, an example of a reaction that leads to a decrease in entropy is: HCl(gas) +NH3(gas) -----> NH4Cl(solid) So you see, there are more gaseous molecules in the reactant side of the equation than in the product side, which means the products are less disordered than the reactants. ----------------------------------------------- However, one must note that if the entropy of a system(reaction) decreases, the entropy of the surroundings should increase. This is because change in TOTAL entropy(A) = change in entropy of SYSTEM(B) + change in entropy of SURROUNDINGS(C). It is a rule that A must increase in every case ( have a positive value). If the B is negative(a decrease in entropy), C must be positive(an increase in entropy) to keep the value of A positive.


Which would represent an increase in entropy?

thawing


What would happen to entropy in a solid to gas reaction?

It increases; more freely moving particles.


Do chemical reactions that increase entropy tend to occur spontaneously?

Reactions that increase the randomness. Reactions that have more moles of gas on the product side than the reactant side increase entropy. Also reactions that have a positive change in spontaneity and a negative enthalpy.


What would cause entropy to increase in reaction?

The products becoming more spread out.


What occurs in a reaction in which the reactant is a solid and the product is a gas?

the answer is D. AS most likely would be positive because a gas has a greater entropy than a solid.


Is Gas produced from a reaction is a phase change and not a chemical change.?

A gas released during a chemical reaction is a chemical change.


What changes a liquid or a solid to a gas?

usually a change in temperature.... OR PRESSURE Which all mean a change in entropy of the system


How do you predict delta s?

delta s (change in entropy) is positive when.... -you go from a solid to a liquid -you go from a liquid to a gas -when you go from a solid to a gas -when there are more mols of products than mols of reactant the change in entropy is negative when the reverse of the above happens