Specific heat capacity of water

In all of these systems, by definition, the specific heat capacity of water is unity. It may be noted that, by comparing the definitions used in the SI and the mks systems, the kilocalorie is equivalent to 4186.8 J/kg K. This quantity has often been referred to as the mechanical equivalent of heat J. 

Calculate the specific enthalpy of water at a pressure of 1 bar and temperature of 200 °C. Check your value using steam tables. The specific heat capacity of water can be calculated from the equation ... 

Assuming that radiation losses amount to 20 kJ/kg of dry air used, determine the mass flow of dry air supplied to the dryer and the humidity of the outlet air. The latent heat of water vapour at 295 K = 2449 kJ/kg, the specific heat capacity of dried material = 0.88 kJ/kg K, the specific heat capacity of dry air = 1.00 kJ/kg K, and the specific heat capacity of water vapour = 2.01 kJ/kg K. 

The specific heat capacity commonly has units of J/g-K. The specific heat capacity of water is 4.18 J/g-K. If we have the specific heat capacity, the mass, and the change of temperature, it is possible to determine the amount of energy absorbed or released (q). 

The specific heat capacity of water is necessary to solve many problems. However, when reading the problem, it is often not apparent that you must use this value. If the problem mentions water, its specific heat capacity will often be part of the solution to the problem. 

From the steam tables in the Appendix, the latent heat of vaporisation of water at 312 K is 2410 kl/kg. Again from steam tables, the specific heat capacity of water vapour = 1.88 kJ/kg K and that of the solids will be taken as 2.18 kl/kg K. 

The chemist uses a coffee-cup calorimeter to neutralize completely 61.1 mL of 0.543 mol/L HCl(aq) with 42.6 mL of NaOH(aq). The initial temperature of both solutions is 17.8°C. After neutralization, the highest recorded temperature is 21.6°C. Calculate the enthalpy of neutralization, in units of kJ/mol of HCl. Assume that the density of both solutions is 1.00 g/mL. Also assume that the specific heat capacity of both solutions is the same as the specific heat capacity of water. 

However, some of these mine waters have significant potential for energy recovery via use of heat pumps. For example, the Morlais mine water of South Wales has an estimated discharge of at least 100 L/s. The specific heat capacity of water is around 4181 J/L/°C or 1.16kWh/m3/ °C. If the Morlais mine water s temperature could be lowered by using a heat pump by 5 °C (from 14 to 9 °C), a heat flux (power) of ... 

A 375 g plug of lead is heated and placed in an insulated container filled with 0.500 L of water. Prior to the immersion of the lead, the water is at 293 K. After a time, the lead and the water assume the same temperature, 297 K. The specific heat capacity of lead is 0.127 J/(g K), and the specific heat capacity of water is 4.18 J/(g K). How hot was the lead before it entered the water (Hint You ll need to use the density of water.)... 

Mass of metal, g Temperature of metal, C Volume of water in calorimeter, litre Initial temperature in calorimeter, °C Maximum temperature of water in calorimeter, °C Increase in temperature of water in calorimeter, K Decrease in temperature of metal, K Specific heat capacity of water, cal/g K Ditto, of glass (from tabulated data), cal/g-K Amount of heat absorbed by glass of beaker and thermometer, cal... 

A catalytic reaction must be performed in aqueous solution at industrial scale. The reaction is initiated by addition of catalyst at 40 °C. In order to evaluate the thermal risks, the reaction was performed at laboratory scale in a Dewar flask. The charge is 150 ml solution in a Dewar of 200 ml working volume. The volume and mass of catalyst can be ignored. For calibration of the Dewar by Joule effect, a heating resistor with a power of 40 W was used in 150ml water. The resistor was switched on for 15 minutes and the temperature increase was 40 K. During the reaction, the temperature increased from 40 to 90 °C within approximately 1.5 hours. The specific heat capacity of water is 4.2 kj kg K 1. 

A catalytic hydrogenation is performed at constant pressure in a semi-batch reactor. The reaction temperature is 80 °C. Under these conditions, the reaction rate is lOmmolT s-1 and the reaction may be considered to follow a zero-order rate law. The enthalpy of the reaction is 540 kj moT1. The charge volume is 5 m3 and the heat exchange area of the reactor 10 m2. The specific heat capacity of water is 4.2kJkg 1K 1. 

A reaction mixture is heated in a vessel fitted with an agitator and a steam coil of area 10 m2 fed with steam at 393 K. The heat capacity of the system is equal to that of 500 kg of water. The overall coefficient of heat transfer from the vessel of area 5 m2 is 10 W/m2 K. It takes 1800 s to heat the contents from ambient temperature of 293 to 333 K. How long will it take to heat the system to 363 K and what is the maximum temperature which can be reached Specific heat capacity of water = 4200 J/kgK. 

Compared with ambient values, the specific heat capacity of water approaches infinity at the critical point and remains an order of magnitude higher in the critical region [26], making supercritical water an excellent thermal energy carrier. As an example, direct measurements of the heat capacity of dilute solutions of argon in water from room temperature to 300 °C have shown that the heat capacities are fairly constant up to about 175-200 °C, but begin to increase rapidly at around 225 °C and appear to reach infinity at the critical temperature of water [29]. 

The specific heat capacity of water is relatively large 4.184 J/g-°C. This value helps to explain how water can absorb and release enough energy to moderate Earth s temperature. Examine the values in Table 14.2. Notice that the specific heat capacities of most substances are much lower than the specific heat capacity of water. 

As well, you know the specific heat capacity of water 4.184 J/g-°C. 

TABLE 1.11. Specific Heat Capacity of Water Relative to Other Substances... 

The model uses the specific heat capacity of water and gases in the ideal state to determine the standard Gibbs free energy of reaction, AG°, i.e., Eq. 9,... 

The high specific heat capacity of water means that distillation requires high energy, and reaction mixtures are difficult to heat or cool rapidly.1261... 

We also need to know the heat required to raise the temperature of a given amount of water by 1°C. Table 9.3 lists the specific heat capacity of water as 4.18 J °C 1 g-1. This means that 4.18 J of energy is required to raise the temperature of 1 g of water by 1°C. 

A certain microwave oven delivers 750. watts (J/s) of power to a coffee cup containing 50.0 g of water at 25.0°C. If the wavelength of microwaves in the oven is 9.75 cm, how long does it take, and how many photons must be absorbed, to make the water boil The specific heat capacity of water is 4.18 J/°C g. Assume only the water absorbs the energy of the microwaves. 

To cite one instance, although a description that the specific heat capacity of water is just 1 cal/(g-K) is simple, another description that the specific heat capacity of water is 4.184 J/(g K) is somewhat complicated. 

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