Answer:
5.7 pH
Explanation:
To find pH when given [H+], you use this formula: pH = -log[H+]
-log * 2.1e-6 = 5.6778 = 5.7 pH
It takes 33.4 s for the concentration of A to fall to one-fourth of its original value.
A <em>half-life</em> is the time it takes for the concentration to fall to half its original value.
Assume the initial concentration is 1.00 mol/L. Then,

The concentration drops to one-fourth of its initial value in two half-lives.
∴ Time = 2 × 16.7 s = 33.4 s
Answer:
Because scientists call vaccines reagents.
In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute<span> is a substance </span>dissolved<span> in another substance, </span>known as<span> a </span>solvent<span>.</span>
<span>Yes, mass is conserved. When sodium hydroxide (clear solution) and copper sulfate (blue solution) are mixed, they form a copper hydroxide (a blue solid) and sodium sulfate (a clear solution).
This can be tested simply. First weigh the masses (10 g and 57 g, which totals 67 g)) of the two starting solutions prior to mixing. Then mix and allow the reaction to occur and weigh the mass of the mixture (10g + 57 g = 67 g). The two solutions should have the same mass and therefore demonstrate conservation of mass.</span>