Answer:
is there a table or an equation for that ??
When a chemical reaction takes place it changes the composition of the reactants. The ways to tell if a reaction is occurring are,
1-Release of heat
2-Production of a gas
3-Formation of a precipitate
4-Change in color
Answer:

Explanation:
We already know that the mass number of an atom is the sum of the number of protons and the number of neutrons.
So, the mass number of this isotope is;
Number of protons = 7
Number of neutrons = 8
Mass number = 7 + 8 = 15
Hence, the isotope is;

Answer:
Kc = 4.774 * 10¹³
Explanation:
the desired reaction is
2 NO₂(g) ⇋ N₂(g) + 2 O₂(g)
Kc =[N₂]*[O₂]² /[NO₂]²
Since
1/2 N₂(g) + 1/2 O₂(g) ⇋ NO(g)
Kc₁= [NO]/(√[N₂]√[O₂]) → Kc₁²= [NO]²/([N₂][O₂])
and
2 NO₂(g) ⇋ 2 NO(g) + O₂(g)
Kc₂= [NO]²*[O₂]/[NO₂]² → 1/Kc₂= [NO₂]²/([NO]²[O₂])
then
Kc₁²* (1/Kc₂) = [NO]²/([N₂]*[O₂]) *[NO₂]²/([NO]²[O₂]) = [NO₂]²/([N₂]*[O₂]²) = 1/Kc
Kc₁² /Kc₂ = 1/Kc
Kc= Kc₂/Kc₁² =1.1*10⁻⁵/(4.8*10⁻¹⁰)² = 4.774 * 10¹³
Answer:
1. Participating in calcium homeostatis storage of calcium.
2. High capacity calcium (Ca) regulation and protection against herbivory