Only when there is no product that is when a chemical reaction has not occured
Answer:
pineal body is a vastigious structure which signifies same origin of chimpanzee and modern man
Explanation:
An acid-base indicator is used to identify the presence of an acid or base. These indicators exhibit different colors depending on the solution that they are in. They are especially useful when completing titrations to determine the molarity of an unknown substance and is denoted as option D.
<h3>What is Titration?</h3>
This is done in the laboratory and involves the slow addition of one solution of a known concentration to a known volume of another solution of unknown concentration.
Acid-base indicators are used to determine the presence of an acid or base in a solution which is based on the colors seen when performing the chemical reaction.
It is used to calculate the the molarity of an unknown substance through the knowledge of the other parameters which is therefore the reason why option D was chosen as the most appropriate choice.
Read more Acid-base indicators here brainly.com/question/2815636
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(missing in Q) : Calculate the concentration of CO & H2 & H2O when the system returns the equilibrium???
when the reaction equation is:
C(s) + H2O(g) ↔ H2(g) + CO(g)
∴ Kc = [H2] [CO] / [H2O]
and we have Kc = 0.0393 (given missing in the question)
when the O2 is added so, the reaction will be:
2H2(g) + O2(g) → 2H2O(g)
that means that 0.15 mol H2 gives 0.15 mol of H2O
∴ by using ICE table:
[H2O] [H2] [CO]
initial 0.57 + 0.15 0 0.15
change -X +X +X
Equ (0.72-X) X (0.15+X)
by substitution:
0.0393 = X (0.15+X) / (0.72-X) by solving for X
∴ X = 0.098
∴[H2] = X = 0.098 M
∴[CO] = 0.15 + X
= 0.15 + 0.098 = 0.248 M
∴[H2O] = 0.72 - X
= 0.72 - 0.098
= 0.622 M
pure substances can be divided into two groups; elements and compounds
