Answer:
A wave with small amplitude.
Explanation:
Amplitude us inversely proportional to energy so the smaller the amplitude, the higher the energy.
Hope it helps.
Answer: 480 kJ of energy is released when 3.5 mol of 
reacts.
Explanation:
The balanced chemical reaction is:
Thus it is given that the reaction is exothermic (heat energy is released) as enthalpy change for the reaction is negative.
1 mole of on reacting gives = 137 kJ of energy
Thus 3.5 moles of on reacting gives = 
of energy
Thus 480 kJ of energy is released when 3.5 mol of reacts.
<h2>Example of Physical change </h2>
Ice forming and then melting back into water are an example of physical change because the nature of water is liquid. Yet when it freezes then it becomes into solid form. The water which is liquid then freezes to form ice form which is as a solid which is also a physical change.
If we see that when ice which is frozen and in solid form starts to melt by heat then it converts into water which is liquid form. This indicates that water freezes to form ice means liquid to solid therefore its shape changes which is a physical change. When ice melts it becomes solid to liquid it also changes shape and subsequently takes a physical change.
