1. A heavy nucleus (U235 or Pu239), when bombarded by slow moving neutrons, split into two
or more nuclei.
2. Two or more neutrons are produced by fission of each nucleus.
3. Huge amount of energy is produced as a result of nuclear fission.
4. All the fission fragments are radioactive, giving off β and radiations.
<span>5. The atomic weights of fission products range from about </span>70 to 160.
6. The nuclear chain reactions can be controlled and maintained steadily by absorbing a
desired number of neutrons. This process is used in nuclear reactor.
<span>7. All the fission reactions are self-propagating chain-reactions because fission products contain </span>
neutrons (secondary neutrons) which further cause fission in other nuclei.
8. Every secondary neutron, released in the fission process, does not strike a nucleus, some
escape into air and hence a chain reaction cannot be maintained.
<span>9. The number of neutrons, resulting from a single fission, is known as the multiplication factor. </span>
When the multiplication factor is less than 1, a chain reaction does not take place.
<span>10. The control of chain reaction is necessary in order to maintain a steady reaction. This is </span>
carried out by absorbing a desired number of neutron by employing materials like
percentage of Cd, B or steel.
11. In a nuclear reactor, the multifactor is one. This is achieved by proper arrangement of
<span>fissionable materials.</span>
Reaction of sodium with water
Sodium metal reacts rapidly with water to form a colourless solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic. During the reaction, the sodium metal may well become so hot that it catches fire and burns with a characteristic orange colour. The reaction is slower than that of potassium (immediately below sodium in the periodic table), but faster than that of lithium (immediately above sodium in the periodic table).
2Na(s) + 2H2O → 2NaOH(aq) + H2(g)
Answer: Because water has a high specific heat capacity due to the hydrogen bonding within the H₂O molecules ; so it takes a great deal of energy, or heat, to break these bonds— or to form them.
______________________________________________________
Answer: 15062.4 Joules
Explanation:
The quantity of heat energy (Q) required to heat a substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)
Thus, Q = MCΦ
Since,
Q = ?
Mass of food = 200.0g
C = 4.184 j/g°C
Φ = (Final temperature - Initial temperature)
= 83.0°C - 65.0°C = 18°C
Then, Q = MCΦ
Q = 200.0g x 4.184 j/g°C x 18°C
Q = 15062.4 J
Thus, 15062.4 joules of heat energy was contained in the food.
Answer:
x = 100 * 1.1897 = 118.97 %, which is > 100 meaning that all of the HClO2 dissociates
Explanation:
Recall that , depression present in freezing point is calculated with the formulae = solute particles Molarity x KF
0.3473 = m * 1.86
Solving, m = 0.187 m
Moles of HClO2 = mass / molar mass = 5.85 / 68.5 = 0.0854 mol
Molality = moles / mass of water in kg = 0.0854 / 1 = 0.0854 m
Initial molality
Assuming that a % x of the solute dissociates, we have the ICE table:
HClO2 H+ + ClO2-
initial concentration: 0.0854 0 0
final concentration: 0.0854(1-x/100) 0.0854x/100 0.0854x / 100
We see that sum of molality of equilibrium mixture = freezing point molality
0.0854( 1 - x/100 + x/100 + x/100) = 0.187
2.1897 = 1 + x / 100
x = 100 * 1.1897 = 118.97 %, which is > 100 meaning that all of the HClO2 dissociates
