Heat, q, is energy transferred between a system and its surroundings. For a process that involves a temperature change q=m. Cs AT where Cs is specific heat and m is mass. Heat can also be transferred at a constant temperature when there is a change in state. For a process that involves a phase change q= n·ΔΗ where, n is the number of moles and AH is the enthalpy of fusion, vaporization, or sublimation. The following table provides the specific heat and enthalpy changes for water and ice. Substance Specific heat (Jg-¹ °C-¹) Part A water ice ΔΗ = 35.1 kJ Submit Calculate the enthalpy change, AH, for the process in which 14.2 g of water is converted from liquid at 17.4 °C to vapour at 25.0 °C. For water, Avap H = 44.0 kJ mol-¹ at 25.0 °C and Cs = 4.18 Jg-¹ °C-¹ for H₂O(1). -1 Express your answer to three significant figures and include the appropriate units. View Available Hint(s) Part B 4.18 2.01 Previous Answers ✓ Correct The enthalpy change is positive because heat is being transferred from the surroundings into the system. ΔΗ (kJ mol-¹) 44.0 6.01 How many grams of ice at -22.6 °C can be completely converted to liquid at 20.6 °C if the available heat for this process is 4.54x103 kJ ? For ice, use a specific heat of 2.01 Jg-1°C-1 and Afus H=6.01kJ mol-¹. Express your answer to three significant figures and include the appropriate units
Ideal and Real Gases
Ideal gases obey conditions of the general gas laws under all states of pressure and temperature. Ideal gases are also named perfect gases. The attributes of ideal gases are as follows,
Gas Laws
Gas laws describe the ways in which volume, temperature, pressure, and other conditions correlate when matter is in a gaseous state. The very first observations about the physical properties of gases was made by Robert Boyle in 1662. Later discoveries were made by Charles, Gay-Lussac, Avogadro, and others. Eventually, these observations were combined to produce the ideal gas law.
Gaseous State
It is well known that matter exists in different forms in our surroundings. There are five known states of matter, such as solids, gases, liquids, plasma and Bose-Einstein condensate. The last two are known newly in the recent days. Thus, the detailed forms of matter studied are solids, gases and liquids. The best example of a substance that is present in different states is water. It is solid ice, gaseous vapor or steam and liquid water depending on the temperature and pressure conditions. This is due to the difference in the intermolecular forces and distances. The occurrence of three different phases is due to the difference in the two major forces, the force which tends to tightly hold molecules i.e., forces of attraction and the disruptive forces obtained from the thermal energy of molecules.
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