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2 years ago

What is true about energy in an ordinary chemical reaction? Energy is

Chemistry

2 answers:

Mila [183]2 years ago

5 0

Answer: third choice, not created or destroyed.

Explanation:

1) During a chemical reaction energy is not either created or destroyed. It is only transferred and the total amount of energy remains constant.

2) That is the first law of thermodynamics, which means that it is a universal true and is verified in any process either chemical or physical.

3) Of course we constantly experience that some form of energy that we observe "dissapears". Well it does not. It is just transformed into other form of energy.

4) In the case of the chemical reactions, whe usually observe that in the form of heat: for example when H₂ reacts with O₂ to form H₂O a considerable amount of heat evolves. That is because potential chemical energy in the bonds of the reactants (O₂ and H₂) is released, this is, some potential chemica energy is transformed into heat and part of the chemical potential energy is in the product bonds.

That is why you can write the expression:

ΔH rxn = ∑ΔH products - ∑ΔH reactants, or

∑ΔH products = ΔH rxn + ∑ ΔH reactants.

Which you must interpret as that the energy of the reactants ends up as energy on the products or heat released by the reaction.

RSB [31]2 years ago

3 0

Energy is not created or destroyed due to the law of Conservation of Energy. Hope this helps!

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In a classical long run supply model the economy is always doing what

ch4aika [34]

Answer:

Economy is always at the full employment level of output

Explanation:

The economy in a classical long-run supply model will always have the same economic output

8 0

2 years ago

Consider the following reaction:

iren [92.7K]

Answer:

A. ΔG° = 132.5 kJ

B. ΔG° = 13.69 kJ

C. ΔG° = -58.59 kJ

Explanation:

Let's consider the following reaction.

CaCO₃(s) → CaO(s) + CO₂(g)

We can calculate the standard enthalpy of the reaction (ΔH°) using the following expression.

ΔH° = ∑np . ΔH°f(p) - ∑nr . ΔH°f(r)

where,

n: moles

ΔH°f: standard enthalpy of formation

ΔH° = 1 mol × ΔH°f(CaO(s)) + 1 mol × ΔH°f(CO₂(g)) - 1 mol × ΔH°f(CaCO₃(s))

ΔH° = 1 mol × (-635.1 kJ/mol) + 1 mol × (-393.5 kJ/mol) - 1 mol × (-1206.9 kJ/mol)

ΔH° = 178.3 kJ

We can calculate the standard entropy of the reaction (ΔS°) using the following expression.

ΔS° = ∑np . S°p - ∑nr . S°r

where,

S: standard entropy

ΔS° = 1 mol × S°(CaO(s)) + 1 mol × S°(CO₂(g)) - 1 mol × S°(CaCO₃(s))

ΔS° = 1 mol × (39.75 J/K.mol) + 1 mol × (213.74 J/K.mol) - 1 mol × (92.9 J/K.mol)

ΔS° = 160.6 J/K. = 0.1606 kJ/K.

We can calculate the standard Gibbs free energy of the reaction (ΔG°) using the following expression.

ΔG° = ΔH° - T.ΔS°

where,

T: absolute temperature

ΔG° = ΔH° - T.ΔS°

ΔG° = 178.3 kJ - 285K × 0.1606 kJ/K = 132.5 kJ

ΔG° = ΔH° - T.ΔS°

ΔG° = 178.3 kJ - 1025K × 0.1606 kJ/K = 13.69 kJ

ΔG° = ΔH° - T.ΔS°

ΔG° = 178.3 kJ - 1475K × 0.1606 kJ/K = -58.59 kJ

5 0

3 years ago

Explain, in terms of electrons, why the radius of a potassium atom is larger than the radius of a potassium ion in the ground st

barxatty [35]

Because the Potassium ion loses an electron, the electrons come a little closer to the nucleus because they are attracted to the protons. This makes the ion smaller in radius

4 0

3 years ago

What does pressure measure

omeli [17]

Answer:

Explanation:

Pressure it says it in the name its the force of colliding particles

6 0

3 years ago

Thermochemical equations are chemical equations that include the __________ of the reaction.

irga5000 [103]

A Thermochemical Equation is a balanced stoichiometric chemical equation that includes the enthalpy change, ΔH. In variable form, a thermochemical equation would look like this:

A + B → CΔH = (±) #

Where {A, B, C} are the usual agents of a chemical equation with coefficients and “(±) #” is a positive or negative numerical value, usually with units of kJ.

please mark as brainliest

5 0

2 years ago