<h2>Answer:</h2>
Option (B):
The products can form reactants, and the reactants can form products.
<h3>Explanation:</h3><h3>Reversible reaction</h3>
A reversible reaction is a reaction where the reactants form products, which react together to give the reactants back.
aA + bB ⇄ cC + dD
A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B.
Other options are wrong because off:
(A) Concentration changes with time equilibrium concentration and higher product concentration is also possible.
(C) They may be constant.
(D) Concentration changes with time equilibrium concentration and higher reactant concentration is also possible.
<h3>
Answer:</h3>

<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Atomic Structure</u>
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
6.022 × 10²² atoms Fe (iron)
<u>Step 2: Identify Conversions</u>
Avogadro's Number
<u>Step 3: Convert</u>
- Set up:

- Divide:

Biuret reagent will indicate the presence of protein in a given sample. It is also known as the Piotrowski's test. This reagent consists of copper (II) sulfate and sodium hydroxide. It detects peptide bonds by the reaction of the copper ions in an alkaline solution. The copper ions would form violet colored complexes when peptide is present in the solution. From this test, concentration can be calculated since the intensity of the color depends on the amount of peptide bonds and according to the Beer-Lambert law concentration and the absorption of light is proportional. The concentration is calculated by a spectrophotometric technique at a wavelength of 540 nm.