Answer:
The enthalpy change for the reaction is ΔH = - 54.3 kJ/mol
Explanation:
The reaction between HCl and NaOH is a neutralization reaction:

Heat released during neutralization = Heat gained by water
i.e. 
where:

m = total mass of solution

ΔT = change in temperature = 22.8 - 21.5 = 1.3 C
c = specific heat = 4.18 J/g C

As per equation (1): qrxn = -434.7 J
The reaction enthalpy ΔH is the heat released per mole of acid (or base)


Answer:
Kinetic Energy is the amount of motion in an object. This comes from Potential Energy, or how much force there can be. Kinetic Energy is current motion.
Answer 2: 1 mole = 6.03 x 1023 particles. One mole of any element has a mass in grams that is equal to its atomic number, and has exactly 6.02 x 1023 atoms - however because the atoms of each element have different sizes and weights, then the volume that each one occupies is different.
Credits to
https://scienceline.ucsb.edu/getkey.php?key=274
It could be a couple different thing, explain more.<span />
They can decay through one of three ways:
alpha decay
beta decay and
gamma decay
ALPHA- particle with two neutrons and two protons is ejected from the nucleus of the radioactive atom. this particle released is called an alpha particle. Only occurs with heavy metals.
BETA- pretty much when a proton is transformed into a neutron, or vise versa. in a beta minus decay, the nuetron decays into a proton and in a beta plus decay, a proton decays into a neutron
GAMMA- the nucleus changes from a high energy state to a low energy state by releasing electromagnetic radiation (photons). the number of protons and neutrons stay the same during this reaction therefore the element is still the same.