A reaction is first order. If the initial reactant concentration is 0.0200 M, and 25.0 days later the concentration is 6.25 x 10-4 M, then its half-life is:
Chemical indicators are the chemical reagents that show the change in reaction by changing color. Chemical indicators must be chosen with a narrow pH range.
<h3>What are indicators?</h3>
Indicators are the solutions or the substances used for the qualitative and the quantitative measurement by a change in color because of the absence or the presence of the sample concentration.
The chemical indicators cannot detect the exact pH and should be used with a narrow range of pH.
Therefore, option C. the narrow range of pH is the disadvantage of chemical indicators.
Learn more about chemical indicators here:
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The atomic structure of the atom contains 9 positively charged particles (protons) and 10 neutrally charged particles (neutrons) in the center of the atom in a clump called the nucleus. Those 9 negatively charged particles (electrons) are moving around outside of the nucleus.
There are 10 neutral charges, because the mass of 19 comes from the number of neutral charges plus the number of positive charges.
To calculate the number of neutral charges, subtract the positive charges from the mass (19 - 9), and you get the number of neutral charges (10).
According to Dalton's Atomic Theory, the <em>Law of Definite Proportion is applied when a compound is always made up by a fixed fraction of its individual elements.</em> This is manifested by the balancing of the reaction.
The reaction for this problem is:
H₂ + Cl₂ → 2 HCl
1 mol of H₂ is needed for every 1 mole of Cl₂. Assuming these are ideal gases, the moles is equal to the volume. So, if equal volumes of the reactants are available, they will produce twice the given volumes of HCl.
