Answer:They indicate the number of molecules of each substance
Explanation:
When we write chemical reaction equations, we usually put a number before the symbol of each reactant.
These coefficient shows the number of molecules of that specie that is involved in the balanced reaction equation for the reaction.
These coefficients are important because they are used in carrying out stoichiometric calculations.
Answer:
The balance equation of Ca(OH)2 + HCl ---> CaCl2 + H2O
is
Ca(OH)2(s) + <u>2</u>HCl(aq) ---> CaCl2(aq) +<u>2</u>H2O (l) (balanced equation)
Max Planck was studying the emission of light by
hot objects. He believed that the hot objects did not emit energy continuously,
as would be expected if it were in the form of waves. Instead he suggested that
the object emits the energy in small, specific amounts called quanta. A quantum
is the minimum quantity of energy that can be lost or gained by an atom. He
proposed the following relationship between a quantum of energy and the
frequency of the radiation: E = hn.
E represents the energy in joules of a quantum of radiation, n<span> is the frequency of the radiation emitted, and
h is a constant known as Planck’s constant. Albert Einstein introduced the idea
that electromagnetic radiation has a dual wave-particle nature. Example: white
light exhibits many wavelike particles, it can also be thought of as a stream
of particles. Each particle of light carries a quantum of energy. He called
these particles photons. A photon is a particle of electromagnetic radiation
having zero rest mass and carrying a quantum of energy.</span>
