Answer:
0.018 moles of isooctane must be burned to produce 100 kJ.
Explanation:
When the isooctane is <em>burned</em>, it undergoes a reaction known as combustion, in which reacts with oxygen to produce carbon dioxide and water. In standard conditions (Pressure = 1 atm and Temperature = 298 K) formed water is liquid. The balanced equation is:
C₈H₁₈(l) + 12.5 O₂(g) ⇄ 8 CO₂(g) + 9 H₂O(l)
The standard enthalpy of combustion (which can be found in tables) relates the amount of isooctane that reacts and the heat the reaction liberates. In this case, ΔH°c = -5,460 kJ/mol, that is every 1 mol of isooctane that burns, 5,460 kJ of heat are released.
We can begin with the information of 100 kJ and apply this conversion factor. Since this energy is released, by convention, we write it with a minus sign.
Answer:
A = 2
B = 1
Explanation:
The atomic number of lithium is 3.
Its atomic mass is 7 amu.
It is present in group group 1.
It has one valance electron.
Lithium is alkali metal it form salts.
It is silvery soft metal. It has lowest density as compared to all other metals.
It react vigorously with water.
It is used in rechargeable batteries which are used in camera, mobile, laptops etc.
The electronic configuration of Li:
Li₃ = 1s² 2s¹
Thus,
A = 2
B = 1
Answer:
11.8.4 Distillation Columns
Distillation columns present a hazard in that they contain large inventories of flammable boiling liquid, usually under pressure. There are a number of situations which may lead to loss of containment of this liquid.
The conditions of operation of the equipment associated with the distillation column, particularly the reboiler and bottoms pump, are severe, so that failure is more probable.
The reduction of hazard in distillation columns by the limitation of inventory has been discussed above. A distillation column has a large input of heat at the reboiler and a large output at the condenser. If cooling at the condenser is lost, the column may suffer overpressure. It is necessary to protect against this by higher pressure design, relief valves, or HIPS. On the other hand, loss of steam at the reboiler can cause underpressure in the column. On columns operating at or near atmospheric pressure, full vacuum design, vacuum breakers, or inert gas injection is needed for protection. Deposition of flammable materials on packing surfaces has led to many fires on opening of distillation column for maintenance.
Another hazard is overpressure due to heat radiation from fire. Again pressure relief devices are required to provide protection.
The protection of distillation columns is one of the topics treated in detail in codes for pressure relief such as APIRP 521. Likewise, it is one of the principal applications of trip systems.
Another quite different hazard in a distillation column is the ingress of water. The rapid expansion of the water as it flashes to steam can create very damaging overpressures.
