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How is an exothermic reaction identified on a potential energy diagram?

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Answered by answersmine AT 22/10/2019 – 02:30 AM

Energy diagrams are use to depict the energy changes that occur during a chemical reaction. There are two types of reaction based on the energy change, these are exothermic and endothermic reactions. In endothermic reactions energy are gained while in exothermic reactions energy are lost to the environment. To identify an exothermic reaction on a potential energy diagram, one has to compare the potential energy of the reactants and the products. If the potential energy of the product is less than that of the reactants, the reaction is exothermic.

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A chemical or physical change that takes in heat from its surroundings is an exothermic process an explosion an endothermic process a phase change

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A chemical or physical change that takes in heat from its surroundings is an exothermic process an explosion an endothermic process a phase change

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Ccording to Le Chatelier’s principle, what happens when the concentration of a product is reduced in a chemical reaction that was in equilibrium? A. The equilibrium shifts to the right to favor the formation of products. B. The equilibrium shifts to the left to favor the formation of reactants. C. The equilibrium shifts in the exothermic direction. D. The equilibrium shifts in the endothermic direction.

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Ccording to Le Chatelier’s principle, what happens when the concentration of a product is reduced in a chemical reaction that was in equilibrium? A. The equilibrium shifts to the right to favor the formation of products. B. The equilibrium shifts to the left to favor the formation of reactants. C. The equilibrium shifts in the exothermic direction. D. The equilibrium shifts in the endothermic direction.

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Which label shows the overall enthalpy change and is the reaction exothermic or endothermic? A, exothermic. B, exothermic. C, endothermic. D, endothermic.

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Please, find attached the image that accompanies this question, which is needed to understand and answer it.

Answer:

  • The label that shows the overall enthalpy change is the label D.
  • The reaction is endothermic.

Thus, the answer is D, endothermic.

Explanation:

You must assume that the base line (the black horizontal line at the bottom, from which the green and black arrows depart) shows the starting enthalpy with which the reactants of the reaction start.

So, the head of the arrow A shows how high the energy of the reaction has increased from the starting energy(that is the activation energy).

From that point, the energy decreases until the line indicated by the head of the arrow D. So, that is how high is the enthalpy of the products resultant of the chemical reaction compared with the enthalpy of the reactants.

The overall enthalpy change (ΔH rxn) is given by the change in the enthalpy of the products less the enthalpy of the reactants:

  • ΔHrxn = ∑H products – ∑ H reactants.

That difference, precisely, is what is shown by the arrow labeled D. So, your first conclusion is that the label that shows the overall enthalpy change is the label D.

As for the second question, an endothermic reaction is that that absorbs energy from the surroundings, and the products end with a higher enthalpy than the reactants. That is what the diagram is showing: the products ended at a higher level than the reactants, so energy was absorbed and the reaction is endothermic.

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– How many moles of NaHCO3 can be produced from 125 mol of NaCl – How many moles Of H2O are produced when 6 mol of O2 is consumed in burning methyl alcohol, CH3OH, according to the following equation? – Solutions of iron(III) chloride, FeCl3, are used in photoengraving and to make ink. This compound can be made by the following reaction. a. How many moles of FeCl3 form from 31 mol of Cl2? b. How many moles of Fe are needed to combine with 5 mol of Cl2 by this reaction? c. If 0.62 mol of Fe is to be used by this reaction, how many moles of FeCl3 form? – Ammonia is produced synthetically by the reaction: a. Is this an exothermic or endothermic process? b. How many moles of NH3 are formed when 1 mol of N2 reacts with hydrogen? c. If 18 x 1023 molecules of H2 react with nitrogen, how many moles of NH3 are produced?

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A positive cahnge of enthalpy, ΔH rxn = + 55 kJ/mol, for the forward reaction means that the reaction is endothermic, i.e. the reactants absorb energy and the products are higher in energy.

Activation energy is the difference in the energy level of the reactants and the peak in the potential energy diagram (the energy of the transition state).

For an endothermic reaction, the products will be closer in energy to the transition state than what the reactans will be; so, the activation energy of the reversed reaction is lower than the activation energy of the forward reaction.

Activation energy of reverse and forward reactions is related by:

Activation energy of reverse rxn = Activation energy of forward rxn – ΔH rxn

=> Activiation energy of reverse rxn = 102 kJ/mol – 55 kJ/mol = 47 kJ/mol

Answer: 47 kJ/mol

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In the important industrial process for producing ammonia (the Haber Process), the overall reaction is: N2(g) + 3H2(g) → 2NH3(g) + 100.4 kJ A yield of NH3 of approximately 98% can be obtained at 200°C and 1,000 atmospheres of pressure. This reaction is: exothermic endothermic

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In the important industrial process for producing ammonia (the Haber Process), the overall reaction is: N2(g) + 3H2(g) → 2NH3(g) + 100.4 kJ A yield of NH3 of approximately 98% can be obtained at 200°C and 1,000 atmospheres of pressure. This reaction is: exothermic endothermic

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In terms of energy, how would you classify the following chemical reaction? 2Cu + O2 + 315kJ → 2CuO A. endothermic B. exothermic C. both endothermic and exothermic D. neither endothermic nor exothermic

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In terms of energy, how would you classify the following chemical reaction? 2Cu + O2 + 315kJ → 2CuO A. endothermic B. exothermic C. both endothermic and exothermic D. neither endothermic nor exothermic

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The reaction below is exothermic: 2so2 (g) o2 (g) 2so3 (g) le châtelier’s principle predicts that ________ will result in an increase in the number of moles of so3 (g) in the reaction container.

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This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

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An exothermic reaction often requires greater safety precautions than an endothermic reaction, because of the amount of ______. A. time needed B. oxygen required C. energy released D. products formed

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An exothermic reaction often requires greater safety precautions than an endothermic reaction, because of the amount of ______. A. time needed B. oxygen required C. energy released D. products formed

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A reaction that absorbs heat from the surroundings is known as a(n) A) exothermic reaction. B) endothermic reaction. C) displacement reaction. D) decomposition reaction

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What we’re looking for here is the gas sample’s molar mass given its mass, pressure, volume, and temperature. Recalling the gas law, we have

 PV = nRT or
 n = frac{PV}{RT}

where R is 0.08206 L atm / mol K, P is the given pressure, T is the temperature, and V is the volume.

Before applying the values given, it is important to make sure that they are to be converted to have consistent units with that of R. 
Thus, we have

P = 736/ 729 = 0.968 atm
T = 28 + 273.15 = 301.15 K
V = 250/1000 = 0.250 L

Now, applying these converted values into the gas law, we have

 n = frac{(0.968 atm)(0.250 L)}{(0.08206 L.atm/mol.K)(301.15 K)}
 n = 0.00979 moles

Given that the mass of the sample is 0.430 g, we have

 molar mass = frac{mass}{number of moles}  
 molar mass = frac{0.430}{0.00979} = 43.9

Thus, the gas sample has a molar mass of 43.9 g/mol.

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