Constant volume bomb

We have seen that a constant-pressure calorimeter and a constant-volume bomb calorimeter measure changes in different state functions at constant volume, the heat transfer is interpreted as A U at constant pressure, it is interpreted as AH. However, it is sometimes necessary to convert the measured value of AU into AH. For example, it is easy to measure the heat released by the combustion of glucose in a bomb calorimeter, but to use that information in assessing energy changes in metabolism, which take place at constant pressure, we need the enthalpy of reaction. 

A zero order gas reaction, A = rR, proceeds in a constant volume bomb with 20% inerts, and the pressure rises from 1.0 to 1.3 atm in 2 min. When the same reaction proceeds at constant pressure of 3 atm and with 40% inerts, what is the fractional change of volume in 4 minutes ... 

AE = q, (valid with constant volume bomb calorimeter)... 

When we mention the constant-volume batch reactor we are really referring to the volume of reaction mixture, and not the volume of reactor. Thus, this term actually means a constant-density reaction system. Most liquid-phase reactions as well as all gas-phase reactions occurring in a constant-volume bomb fall in this class. 

Burning, Laminar, of Gases. Influence of pressure and temperature on the laminar burning velocity of stoichiometric acetylene-air mixtures using a constant-volume bomb method is described by M.L. Agrawal S.P. Sharma in UnivRoorkeeResJ(India), 8(3-4), Part 11, 81-102(1965) (in Engl)... 

In such cases this is usually determined for convenience in a constant-volume bomb at an initial pressure of 1 atm of inert gas. 

In a constant-volume bomb calorimeter with a heat capacity of 13.418 kJ/K, 1.17 g of naphthalene, C10H8, is burned. Fifty-two joules of energy are required to ignite the sample. If the temperature rise of the calorimeter is 3.318 K, what is the A U and AH of combustion of naphthalene What is the AHy of naphthalene (You may assume that all water is formed in the liquid phase.)... 

The heat combustion (AH) of tungsten carbide at 300 K is -285.65 kcal/mole WC, and the reaction is WC(s) + (5/2)02(g) - W03(s) + C02(g). Compute the heat for the same reaction if it takes place in a constant-volume bomb calorimeter at 300 K. Assume that the gases behave ideally and that corrections to standard states are negligible for solid species. 

Combustion of table sugar produces C02(g) and H20(/). When 1.46 g of table sugar is combusted in a constant-volume (bomb) calorimeter, 24.00 kj of heat is liberated, a. Assuming that table sugar is pure sucrose,... 

J.C. Keck and H. Hu, Explosions of Abiabatically Compressed Gases in a Constant Volume Bomb, 21st Symp. (Int.) Comb. (1986) pp. 521-529. 

A bomb calorimeter is useful for measuring the energy released in combustion reactions. The reaction is carried out in a constant volume bomb with a high pressure of oxygen. How much heat is evolved when 54.0 g glucose (C6Hi20s) is burned according to this equation ... 

Heat Transfer at Constant Volume Bomb Calorimeters... 

Heat of combustion is usually measured by placing a known mass of a compound in a steel container called a constant-volume bomb calorimeter, which is fdled with oxygen at about 30 atm of pressure. The closed bomb is immersed in a known amount of... 

FIGURE 6.6 A constant-volume bomb calorimeter. The calorimeter is filled with oxygen gas before it is placed in the bucket. 

A quantity of 1.435 g of naphthalene (CioHg), a pungent-smeUing substance used in moth repellents, was burned in a constant-volume bomb calorimeter. Consequently, the temperature of the water rose from 20.17°C to 25.84°C. If the mass of water surrounding the calorimeter was exactly 2000 g and the heat capacity of the bomb calorimeter was 1.80 kJ/°C, calculate the heat of combustion of naphthalene on a molar basis that is, find the molar heat of combustion. 

A 0.1375-g sample of solid magnesium is burned in a constant-volume bomb calorimeter that has a heat capacity of 1769 J/°C. The calorimeter contains exactly 300 g of water, and the temperature increases by 1.126°C. Calculate the heat given off by the burning Mg, in kJ/g and in kJ/mol. 

The enthalpy of combustion of benzoic acid (CgHsCOOH) is commonly used as the standard for calibrating constant-volume bomb calorimeters its... 

A thermally insulated (adiabatic) constant-volume bomb has been very carefully prepared so that half its volume, is filled with water vapor and half with subcooled liquid water, both at — 10°C and 0.2876 kPa (the saturation pressure of the subcooled liquid). Find the temperature, pressure, and fraction of water in each phase after equilibrium has been established in... 

Understand the relation between specific heat capacity and heat transferred in both constant-pressure (coffee-cup) and constant-volume (bomb) calorimeters ( 6.3) (SPs 6.3-6.5) (EPs 6.17-6.30)... 

The heats of combustion of hydrocarbons are presently determined by using a constant volume bomb calorimeter for liquids and solids and a constant pressure flame calorimeter for gases. These measurements can be very accurate (< 1 percent), since they depend mainly on the bath temperature measurement. However, calorimetric measurements cannot be made on-line and require information about the thermal properties of the combustion products of the test sample. Tire technique reported here, on the other hand, is direct, can be performed on-line, and requires no prior knowledge about the exact composition of the test sample. (The only assumption made regarding the composition is that saturated hydrocarbons are the only combustibles present in the test samples). It thus appears that this new technique may be more useful for field operations where on-line measurements of the heats of combustion of the test gases are often needed. 

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