Which substance has a standard enthalpy of formation of zero?

Q: Measurements show that the enthalpy of a mixture of gaseous reactants decreases by 225. kJ during a…

A: a.) To Calculate the change in energy of the gas mixture , we would use first law of thermodynamics.…

Q: 4. A 5.00 gram sample of an unknown metal was placed in a beaker of boiling water (99.58 °C). After…

A:

Q: A system does 467 kJ of work and loses 157 kJ of heat to the surroundings. What is the change in…

A: First law of thermodynamics It states states that heat is a form of energy, and thermodynamic…

Q: Measurements show that the energy of a mixture of gaseous reactants increases by 368. kJ during a…

A: We have to calculate the change in enthalpy and nature of reaction.

Q: A student transferred 50.0 mL 1.00 M HCl into a coffee-cup calorimeter, which had a temperature of…

A: Given: Volume of  HCl=  50.0mL Concentration of HCl= 1.00M Volume of NaOH= 50.0 mL Concentration of…

Q: A sample of solid lithium bromide and calcium chloride  were put in a lab for an hour. Their…

A: When 1 mol of a ionic substance is dissolve in water to form a solution at infinite dilution is…

Q: Compare and contrast enthalpy change, molar enthalpy, and quantity of heat transferred to the…

A: Introduction :  Calorimetry can be defined as the process of measuring the amount of heat released…

Q: Balancing Equations Worksheet Using your newly-found equation, balancing knowledge, balance the…

A: Since you have posted a question with multiple sub-parts, we will solve first three sub-parts for…

Q: 1. A sample of metal with mass 250.0 g is heated to 130.0 ℃ and dropped into 425 g of water at 26.0…

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Q: Measurements show that the energy of a mixture of gaseous reactants increases by 369. kJ during a…

A: We have to calculate the change in enthalpy and nature of reaction.

Q: Measurements show that the enthalpy of a mixture of gaseous reactants increases by 391kJ during a…

A: According to the question,The enthalpy of a mixture of gaseous reactants is increased by ΔH = 391…

Q: A chemical reaction in a bomb calorimeter evolves 3.15 kJ of heat. If the temperature of the…

A: From given data q = 3.15 kJ = 3150 J  T1= 19.19°C = 292.19 K T2= 22.03°C = 295.03 K  Formula used…

Q: . You mix 45.00ml of 2.50M HI with 35.00ml of 3.00M KOH, and the temperature of the resulting…

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Q: N2(g) + 3 H2(g) → 2 NH3(g);  ΔH = −91.8 kJ How much heat is released when 1.521 ✕ 104 grams of…

A: Step 1: Here, for the given process, the heat released in formation of 2 moles of ammonia is given…

Q: Measurements show that the energy of a mixture of gaseous reactants increases by 385. kJ during a…

A: We have to calculate the change in enthalpy and nature of reaction.

Q: The reaction between sodium metal and chlorine gas produces 822 kJ of heat energy for every chlorine…

A: GIven, Mass of Na = 4.595g

Q: Measurements show that the energy of a mixture of gaseous reactants decreases by 305. kJ during a…

A: From the first law of thermodynamics, ∆U=∆H+W where delta U is the change in energy, delta H is the…

Q: The standard enthalpy of formation of hydrogen chloride gas, HCI(g) is -92.31 kJ/mol. Write the…

A: The objective of the question is to write the thermochemical equation to represent formation of…

Q: metal X =48.1g; specific heat capacity =0.228 J/C If metal X is heated to 95.1C and put into a…

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Q: H2O(g)is −241.82kJ/mol The standard enthalpy of formation for CO2(g)is −393.5kJ/mol The standard…

A: Given data is The standard enthalpy of formation for H2O (g)is −241.82 kJ/mol The standard enthalpy…

Q: Two metal objects, A and B, each of mass 60.0 g, are prepared at different temperatures. They are…

A: The initial temperature, Ti, of object A is; Q=mcsTf-TiAt thermal equilibrium, QA=QB60 g×0.160…

Q: Measurements show that the energy of a mixture of gaseous reactants decreases by 209. kJ during a…

A: Decrease in Energy of gaseous reactant  = ∆E = -209 kJ Work done = -104 kJ Change in enthalpy of gas…

Q: A gaseous fuel mixture contains 24.2% methane (CH4), 40.5% ethane (C₂H6) and the rest propane (C3H8)…

A: Given, Methane (CH4) = 24.2 %Ethane (C2H6) = 40.5 %Propane (C3H8)=35.3 %

Q: Measurements show that the energy of a mixture of gaseous reactants increases by 275. kJ during a…

A: Here we are given that, energy of a mixture of gaseous reactants increase by 275 kJ. Also 109 kJ of…

Q: Why are fractional coefficients permitted in a balanced thermochemical equation? Fractional…

A: Why are fractional coefficients permitted in a balanced thermo chemical equation? Fractional…

Q: Calculate the standard enthalpy of formation for diamond given the following reactions and using…

A: Given  C(graphite) + O2(g)    →  CO2 (g)              ΔH  = -393.5 kJ                  ( Equation 1…

Q: The enthalpy for formation of NH3(g) is -45.9 kJ/mol. What is the reaction enthalpy for the…

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Q: A scientist measures the standard enthalpy change for the following reaction to be 84.6 kJ :…

A: Known Value:∆Hf°NH4Cl (aq)  = Standard enthapy of formation of NH4Cl (aq)…

Q: A calorimeter is calibrated by mixing two aqueous solutions each with a volume equal to 44.4 mL. The…

A: Given data:Calculate the heat evolved in the reaction of HCl and NaOH and enthalpy of…

Q: The reaction between sodium metal and chlorine gas produces 822 kJ of heat energy for every chlorine…

A:

Q: The work done to compress a gas is 70 J.  As a result, 25 J of heat is given off to the…

A: Work done to compress = Work done on the system And work done on the system is taken with a positive…

Q: what is the initial temperature of the water

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Q: A mixture of gaseous reactants is put into a cylinder, where a chemical reaction turns them into…

A: Given: The pressure of the mixture is 1 atm. The heat released is 349 kJ. The heat that flows in…

Q: 6 & 7. Consider the following reaction: 2 CH,OH (g) → 2 CH(9) + O2 (g), AH = + 252.8 kJ a) Is this…

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Q: A 4.1-g sample of Colorado oil shale is burned in a bomb calorimeter, which causes the temperature…

A: Mass of the colarado oil = 4.1 g

Q: 100.0 ml of 0.115 m potassium hydroxide solution is mixed with 75.0 ml of 0.245 M nitric acid…

A: Given: The volume of 0.115 M KOH and 0.245 M HNO3 is 100.0 mL and 75.0 mL, respectively. The initial…

Q: A 1.595 g samples of a new organic material is combusted in a bomb calorimeter. The temperature of…

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Q: A change in a system occurs such that 31.1 J of work is done by the surroundings and 22.4 J of heat…

A: Internal energy is the stored energy of the system. From the first law of thermodynamics it is clear…

Q: A chemist carefully measures the amount of heat needed to raise the temperature of a 267.0 mg sample…

A: The amount of heat needed to raise the temperate by :Here,

Thermochemistry

Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.    

Exergonic Reaction

The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.