Answer:
the heat source must be greater than 100°C
the water must be permitted to evaporate quickly
the system must be sealed and become pressurized above atmospheric pressure
the vapor pressure must be kept below 760 mmHg
Explanation:
A superheated water is a dry form of steam in which hydrogen bonds that strongly binds the molecules of water has been overcome.
Superheated water finds application in a wide range of places. For example they are used for sterilization of clinical equipment.
- To produce steam or superheated water, the temperature of the source must be greater than the boiling temperature and less than the critical temperature at 374°C.
- Since superheated water is steam and steam is water in gaseous form. The water must be made to evaporate more quickly than it should condense back.
- High pressure and sealing the system helps to produce superheated water very fast.
- If the pressure between the vapor is kept low, water will boil faster.
When the entropy change of vaporization
= enthalpy of vaporization/boiling point temperature
when we have the enthalpy of vaporization = 38560 J/mol
and the boiling point temperature in Kelvin = 78.3 + 273 = 351.3 K
by substitution:
∴the entropy change of vaporization = 38560J/mol/351.3K
= 109.76 J/K/mol
and when the liquid has lesser entropy than the gas and we here convert from
gas to liquid so, the change in entropy = -109.76 J/K/mol
now, we need the moles of C2H5OH = mass/molar mass when the molar
mass of C2H5OH = 46 g/mol and mass = 42.2 g
∴ moles of C2H5OH = 42.2 g / 46 g/mol = 0.92 moles
when 1 mol of C2H5OH turns in liquid entropy change →-109.76 J/K/mol
∴ 0.92 mol of C2H5OH → X
∴ X entropy change when 0.92 mol = -109.76 *0.92 mol / 1 mol
= 84.64 J/K
The answer to this question is that <span>the strong base will require less HCl to bring the pH to 7 than the weak base.
The string base ionizes completely so the [OH-] will be neutralized faster. The weak base has an equilibrium that will constantly shift</span> to compensate for any [OH-] loss, meaning more HCl will be needed to titrate it to lower pH.
Answer:
Capillarity , Adhesion and cohesion . The unique property of water enable life to exist . The most important property of water is movement of materials due to water , maintenance and growth and reproduction .
Explanation:
Chemical reaction is any process that involves rearangent of the molecular or ionic structure of substances. each chemical reaction is characterised by an activation energy required for the reaction to occur ,for the change or rearrangement to take place
now fro combustion of fuel:we provide this energy by spark (heat pulse).now what about electrolysis?just the mode and manner of providing energy is different:instead of talking of activation energy,we talk of activation overpotential,both bring conceptually the same thing.heat energy is replaced by potential difference in rough terms.
so in short ,electrolysis is a chemical change ,just the mode of activation is different that thermally initiated chemical reactions
