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)
Water can't cool at a single temperature. It must start at a higher temperature, and drop to a lower temperature in order to cool. Unless we know the other temperature, there is no way to calculate the amount of thermal energy released.
Answer:
The final temperature of water is 54.5 °C.
Explanation:
Given data:
Energy transferred = 65 Kj
Mass of water = 450 g
Initial temperature = T1 = 20 °C
Final temperature= T2 = ?
Solution:
First of all we will convert the heat in Kj to joule.
1 Kj = 1000 j
65× 1000 = 65000 j
specific heat of water is 4.186 J /g. °C
Formula:
q = m × c × ΔT
ΔT = T2 - T1
Now we will put the values in Formula.
65000 j = 450 g × 4.186 J /g. °C × (T2 - 20°C )
65000 j = 1883.7 j /°C × (T2 - 20°C )
65000 j/ 1883.7 j /°C = T2 - 20°C
34.51 °C = T2 - 20°C
34.51 °C + 20 °C = T2
T2 = 54.5 °C
H will definitely be positive because a bond is always more stable than no bond surely if it is a sigma bond.
For G you can't really know because you don't know how much energy is provided by the bond and if it outways the loss in disorder.
The reaction will become more spontaneous with a lower temperature because H tells you the reaction is exotherm
Answer:
596 g of CO₂ is the mass formed
Explanation:
Combustion reaction:
C₂H₄(g) + 3O₂(g) → 2CO₂(g) + 2H₂O(g)
We determine moles of ethylene that has reacted:
189.6 g . 1mol / 28g = 6.77 moles
We assume the oxygen is in excess so the limiting reagent will be the ethylene.
1 mol of ethylene produce 2 moles of CO₂ then,
6.77 moles will produce the double of CO₂, 13.5 moles.
We convert the moles to mass: 13.5 mol . 44 g /1mol = 596 g
