Answer: Yes the statement is true.
Explanation: Endorphins are chemicals produced by the human bodies to relieve stress and pain.
They are produced mainly by brain and help to transmit electrical signals within nervous system, thus are called as neurotransmitters.
They are also called as "feel good chemicals" as they can act as pain relievers and happiness booster and thus lead to better emotional health.
Answer:
Minera and Aragonite
Explanation:
Limestone is a common type of carbonate sedimentary rock. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO 3). Limestone forms when these minerals precipitate out of water containing dissolved calcium.
Answer:
what? can you translate it in english
Explanation:
I have no explanation and i have no idea
Answer:
There are 4 tryptophans in the protein.
Explanation:
According to question, protein contains one tyrosine residue and say x number of tryptophans.
Concentration of protein solution = 1.0 micromolar = 
Molar absorptivity of a protein solution : 


Length of the cuvette = l = 1.0 cm
Absorbance of protein solution at 280 nm = A = 0.024
( Beer-Lambert's law)

Solving for x :
x = 4
There are 4 tryptophans in the protein.
-20.16 KJ of heat are released by the reaction of 25.0 g of Na2O2.
Explanation:
Given:
mass of Na2O2 = 25 grams
atomic mass of Na2O2 = 78 gram/mole
number of mole = 
= 
=0. 32 moles
The balanced equation for the reaction:
2 Na2O2(s) + 2 H2O(l) → 4 NaOH(aq) + O2(g) ∆Hο = −126 kJ
It can be seen that 126 KJ of energy is released when 2 moles of Na2O2 undergoes reaction.
similarly 0.3 moles of Na2O2 on reaction would give:
= 
x = 
= -20.16 KJ
Thus, - 20.16 KJ of energy will be released.