D is a correct Lewis Dot structure. Nitrogen has 4 valence electrons.
Answer:
What can cause excessive pressure on the high side of an active self-contained recovery device? A closed recovery tank inlet valve or excessive air or other non condensables in the recovery tank (either A or B) Portable refillable tanks or containers used to ship recovered refrigerants must meet what standard(s)?
Explanation:
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Answer:
The actual Van't Hoff factor for AlCl3 is 3.20
Explanation:
Step 1: Data given
Molarity of AlCl3 = 0.050 M
osmotic pressure = 3.85 atm
Temperature = 20 °C
Step 2: Calculate the Van't Hoff factor
AlCl3(aq) → Al^3+(aq) + 3Cl^-(aq)
The theoretical value is 4 ( because 1 Al^3+ ion + 3 Cl- ions) BUT due to the interionic atractions the actual value will be less
Osmotic pressure depends on the molar concentration of the solute but not on its identity., and is calculated by:
π = i.M.R.T
⇒ with π = the osmotic pressure = 3.85 atm
⇒ with i = the van't Hoff factor
⇒ with M = the molar concentration of the solution = 0.050 M
⇒ with R = the gas constant = 0.08206 L*atm/K*mol
⇒ with T = the temperature = 20 °C = 293.15 Kelvin
i = π /(M*R*T
)
i = (3.85) / (0.050*0.08206*293.15)
i = 3.20
The actual Van't Hoff factor is 3.20
Answer: A. Liquefy hydrogen under pressure and store it much as we do with liquefied natural gas today.
Explanation:
Current Hydrogen storage methods fall into one of two technologies;
- <em>physical storage</em> where compressed hydrogen gas is stored under pressure or as a liquid; and
- <em>chemical storage</em>, where the hydrogen is bonded with another material to form a hydride and released through a chemical reaction.
Physical storage solutions are commonly used technologies but are problematic when looking at using hydrogen to fuel vehicles. Compressed hydrogen gas needs to be stored under high pressure and requires large and heavy tanks. Also, liquid hydrogen boils at -253°C (-423°F) so it needs to be stored cryogenically with heavy insulation and actually contains less hydrogen compared with the same volume of gasoline.
Chemical storage methods allow hydrogen to be stored at much lower pressures and offer high storage performance due to the strong binding of hydrogen and the high storage densities. They also occupy relatively smaller spaces than either compressed hydrogen gas or liquified hydrogen. A large number of chemical storage systems are under investigation, which involve hydrolysis reactions, hydrogenation/dehydrogenation reactions, ammonia borane and other boron hydrides, ammonia, and alane etc.
Other practical storage methods being researched that focuses on storing hydrogen as a lightweight, compact energy carrier for mobile applications include;
- Nanostructured metal hydrides
- Liquid organic hydrogen carriers (LOHC)
Answer:
Removal of Third Electron
Explanation:
a major jump is required to remove the third electron. In general, successive ionization energies always increase because each subsequent electron is being pulled away from an increasingly more positive ion.
Ionization energy increases from bottom to top within a group, and increases from left to right within a period.
