Hello There!
A Heat Pack is An Example Of A Endothermic Process.
An Endothermic Reaction Is A Reaction That Requires Energy To Move Forward.
Change in energy is E=hc/wavelength of emitted photon
Most of the substances found on earth are compounds.
(water is made up of 2 elements)
(a baseball is larger than a golf ball by default)
(water has a pH value of 7)
Hope this helps u!
Answer: 1. 0.045moles
2. 2.10 grams
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
1. 
2. Mass of 
The element in period 4 of the Periodic Table with the highest electronegativity is krypton (2.96).
