standard enthalpy

A bomb calorimeter, or constant volume calorimeter, is a device often used to determine the heat of combustion of fuels and the energy content of foods. Since the "bomb" itself can absorb energy, a separate experiment is needed to determine the heat capacity of the calorimeter. This is known as calibrating the calorimeter. In the laboratory a student burns a 0.565-g sample of 1-naphthoic acid (C11H8O2) in a bomb calorimeter containing 1120. g of water. The temperature increases from 25.70 °C to 28.70 °C. The heat capacity of water is 4.184 J g-1°C-1. The molar heat of combustion is −5138 kJ per mole of 1-naphthoic acid. C11H8O2(s) + 12 O2(g) 11 CO2(g) + 4 H2O(l) + Energy Calculate the heat capacity of the calorimeter.

The enthalpy change for the reaction of hydrogen gas with fluorine gas to produce hydrogen fluoride is -542 kJ for the equation as written: H2(g) + F2(g) → 2 HF(g)    ΔH = -542 kJ Is the reaction exothermic or endothermic as written?

The standard molar enthalpy of formation of NH3(g) is –45.9 kJ/mol. What is the enthalpy change if 9.10 g N2(g) and 1.82 g H2(g) react to produce NH3(g)?

Calculate the enthalpy of oxidation of two moles of carbon monoxide two make two moles of carbon dioxide 2CO(g) + O2(g)  →  2CO2(g)  ΔH = ? (in kJ) Using the following information: C(s) + O2(g)  →  CO2(g)  ΔH = -393.5 kJ 2C(s) + O2(g)  →  2CO(g)  ΔH = -221.0 kJ

A chemist measures the enthalpy change AH during the following reaction: 3 CH₂ Br(g) + NH3(g) →(CH₂)₂N(1) + 3 HBr(g) 3 Use this information to complete the table below. Round each of your answers to the nearest kJ/m reaction AH=73. kJ 12CH₂Br(g) + 4NH₂(g) → 4(CH₂) N(1) + 12HBr (g) 3 5(CH₂)₂N(1) + 15HBr (g) 3 (CH₂)₂N(/) + 3HBr(g) → 3CH₂Br(g) + NH₂ (g) 3 ONS LE-N 15 CH₂ Br(g) + 5NH, (g) ΔΗ 0 kJ Пк ㅁ kJ kJ

Consider the reaction of chlorine with water vapor, H₂O(g) to form hydrogen chloride and oxygen: 1/2 Cl₂(g) + H₂O(g) = HCl(g) + 1/4 O₂(g) (a) What is the enthalpy change for the reverse reaction? AH reverse ΔΗ= (b) Balance the forward reaction with whole-number coefficients. What is AH for the reaction represented by this equation? kJ/mol. ---Select--- AH = 28.6 kJ kJ/mol. (c) Which is more likely to be thermodynamically-favored, the forward reaction or the reverse reaction? AH should ---Select--- (d) If the (forward) reaction were written to consume liquid water, H₂O(1), instead of water vapor, would you expect the magnitude of AH to increase (become more positive), decrease (become more negative), or stay the same?

Enthalpy of formation of phenol (C6H5OH) is -165 kJ/mol , and enthalpies of formation of CO2 and H2O are -394 kJ/mol and -286 kJ/mol, respectively. What is enthalpy of combustion of phenol?

Given the following two reactions and their enthalpy changes,             2 ClO2 (g)   -->   Cl2 (g)   +   2 O2 (g)                                      Delta H =  – 204 kJ             2 TiCl4 (l)   +   2 O2 (g)    -->    2 TiO2 (s)   +   4 Cl2                Delta H =  – 139.8 kJ What is the value of the enthalpy change for the reaction that is the sum of these two reactions?             2 ClO2 (g)   +  2 TiCl4 (l)    -->   2 TiO2 (s)   +   5 Cl2            Delta H =  ?   a. – 64 kJ b. – 204 kJ c. 64 kJ d. 344 kJ e. 64.2 kJ f. none of these g. – 344 kJ

When methanol, CH, OH, is burned in the presence of oxygen gas, O,, a large amount of heat energy is released, as shown in the combustion reaction. CH;OH(g) + 0,(g) → CO,(g) + 2 H,0(1) ΔΗ-764 kJ Based on the balanced thermochemical reaction, how much heat is produced when 33.1 g of methanol reacts with 51.3 g of oxygen? heat: kJ Which reactant is limiting? охудen methanol