Fission energy is gained by splitting apart heavy atoms fusion is combining light atoms
18. <span>Answer is </span>
A<span>
<span>Since the enthalpy of reaction is positive, the
forward reaction is<span> an endothermic reaction which means the energy
is gained from the surrounding to happen the reaction. If the temperature
decreases, according to the </span></span>Le Chatelier's principle, the system tries to become equilibrium
by increasing temperature. Since forward reaction is endothermic (because of
the bond breaking), the backward reaction is exothermic (because of the bond
making) which releases the energy to the surroundings. This makes the increase
of temperature. So if the backward reaction is promoted because of the decrease
of temperature, then the concentration of H</span><span>₂ will decrease.</span>
<span>
</span>
19. Answer is A.
The reactant side
has 2 moles/molecules of reactants and the product side has 4 moles/molecules
of products which come from 1 N₂(g) and 3 H₂<span>(g). If the pressure is reduced in the system, according to the Le Chatelier's principle, the
system tries to increase the pressure. </span><span>Hence, forward
reaction is promoted because of the higher number
of molecules in product side. If the forward reaction is promoted, the
concentration of NH</span>₃(g) will decreased.
<span>20. </span>Answer is C.
If the concentration
of reactant is increased in the
system, according to the Le Chatelier's principle, the system tries
to reduce the concentration of that reactant. So if NH₃(g) concentration
is increased, then to be equilibrium, the forward reaction will be promoted.
Then the concentration of N₂<span>(g) will increase.</span>
<span> </span>
Answer:
This phenomenon occurs because the door, being metal and leading to changes in temperature, undergoes proportional and morphological changes, metals face expansion and expansion in the presence of heat, called thermal expansion.
On the other hand, against the cold, thermal contraction is suffered, that is why its volume decreases, and it contracts.
Explanation:
The expansion phenomenon of the door is not linear, since it increases its volume in width and height, therefore simultaneously on the entire surface.
When an area or surface expands, it does so by increasing its dimensions in the same proportion. For example, a metal sheet increases its length and width, which means an increase in area. Area dilation differs from linear dilation in that it involves an increase in area.
The area expansion coefficient is the increase in area that a body of a certain substance experiences, with an area equal to unity, as its temperature rises one degree centigrade. This coefficient is represented by the Greek letter gamma.
Regarding shrinkage, a clear example of this is when a metal foundry or a weld shrinks, sometimes it is difficult to understand with examples like these (doors) because it is little noticeable by our eyes and the dimensional changes for our perspective. it is infima.
Properties of a compound is completely different from their elements.
Water is composed by hydrogen and oxygen.
For example, the boiling point of oxygen is - 183 °C and hydrogen is - 253 °C, meanwhile, water has a boiling point of 100°C
Another example is when you put a burning wooden splint into oxygen, it burns more brightly. Put it in hydrogen, you may hear a "pop" sound, or even explode when large amount of hydrogen. But if u put a burning splint in water, it goes off.
