Heat capacity of calorimeter

Figure 4.33 shows a sketch of an adiabatic calorimeter. With an adiabatic calorimeter an attempt is made to follow the temperature increase of an internally heated calorimeter raising the temperature of the surroundings so that there is no net heat flux between the calorimeter and surroundings. The electrically measured heat input into the calorimeter, coupled with the measurement of the sample temperature, gives the information needed to compute the heat capacity of calorimeter plus sample. If truly adiabatic conditions could be maintained, the heat input, AH,, divided by the temperature change, AT, would already be the heat capacity. Subtracting the heat absorbed by the empty calorimeter, its water value, C°, completes the data analysis. 

The heat capacity of a gas at constant pressure is nonually detenuined in a flow calorimeter. The temperature rise is detenuined for a known power supplied to a gas flowing at a known rate. For gases at pressures greater than about 5 MPa Magee et al [13] have recently described a twin-bomb adiabatic calorimeter to measure Cy. 

Solution calorimetry covers the measurement of the energy changes that occur when a compound or a mixture (solid, liquid or gas) is mixed, dissolved or adsorbed in a solvent or a solution. In addition it includes the measurement of the heat capacity of the resultant solution. Solution calorimeters are usually subdivided by the method in which the components are mixed, namely, batch, titration and flow. 

Magee J W, Blanco J C and Deal R J 1998 High-temperature adiabatic calorimeter for constant-volume heat capacity of compressed gases and liquids J. Res. Natl Inst. Stand. Technol. 103 63... 

Bomb calorimeter. The heat flow, q, for the reaction is calculated from the temperature change multiplied by the heat capacity of the calorimeter, which is determined in a preliminary experiment... 

Knowing the heat capacity of the calorimeter, the heat flow for any reaction taking place within the calorimeter can be calculated (Example 8.3). 

Isooctane is a primary component of gasoline and gives gasoline its octane rating. Burning 1.00 mL of isooctane (d = 0.688 g/mL) releases 33.0 kj ofheat. When 10.00 mL of isooctane is burned in a bomb calorimeter, the temperature in the bomb rises from 232°C to 66.5°C. What is the heat capacity of the bomb calorimeter ... 

WEB When one mole of caffeine (CgHlaN402) is burned in air, 4.96 X 103 kj ofheat is evolved. Five grams of caffeine is burned in a bomb calorimeter. The temperature is observed to increase by 11.37°Q What is die heat capacity of the calorimeter in J/°C ... 

Calculate the heat capacity of this calorimeter when it contains 0.200 L of water. 

The heat capacity of an object is the ratio of the heat supplied to the temperature rise produced. Heat transfers are measured by using a calibrated calorimeter. 

A thermogram from a differential scanning calorimeter. The peak indicates a phase change in the sample, and the difference in base line before and after the phase transition is due to the difference in heat capacities of the two phases. 

When 0.113 g of benzene, C6H6, burns in excess oxygen in a calibrated constant-pressure calorimeter with a heat capacity of 551 J-(°C) I, the temperature of the calorimeter rises by 8.60°C. Write the thermochemical equation for... 

A calorimeter was calibrated with an electric heater, which supplied 22.5 kj of energy to the calorimeter and increased the temperature of the calorimeter and its water bath from 22.45°C to 23.97°C. What is the heat capacity of the calorimeter ... 

The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113°C to 22.799°C. The calorimeter assembly is known to have a total heat capacity of 3.00 kJ-(°C). (a) Write a balanced equation for the reaction. 

The ABC cereal company is developing a new type of breakfast cereal to compete with a rival product that they call Brand X. You are asked to compare the energy content of the two cereals to see if the new ABC product is lower in calories so you burn 1.00-g samples of the cereals in oxygen in a calorimeter with a heat capacity of 600. J-(°C). When the Brand X cereal sample burned, the temperature rose from 300.2 K to 309.0 K. When the ABC cereal sample burned, the temperature rose from 299.0 K to 307.5 K. (a) What is the heat output of each sample (b) One serving of each cereal is 30.0 g. How would you label the packages of the two cereals to indicate the fuel value per 30.0-g serving in joules in nutritional Calories (kilocalories) ... 

Normally, when sulfur is oxidized, the product is S02, but S03 may also be formed. When 0.6192 g of sulfur was burned, by using ultrapure oxygen in a bomb calorimeter with a heat capacity of 5.270 kJ-(°C) 1, the temperature rose 1.140°C. Assuming that all the sulfur was consumed in the reaction, what was the ratio of sulfur dioxide to sulfur trioxide produced ... 

A number of other thermodynamic properties of adamantane and diamantane in different phases are reported by Kabo et al. [5]. They include (1) standard molar thermodynamic functions for adamantane in the ideal gas state as calculated by statistical thermodynamics methods and (2) temperature dependence of the heat capacities of adamantane in the condensed state between 340 and 600 K as measured by a scanning calorimeter and reported here in Fig. 8. According to this figure, liquid adamantane converts to a solid plastic with simple cubic crystal structure upon freezing. After further cooling it moves into another solid state, an fee crystalline phase. 

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