The pH of a solution prepared by the addition of 100mL 0.002M HCL to 100mL distilled water is closest to: a.1.0
b.1.5
c.2.0
d.3.0

d.3.0

Explanation:

Step 1: Calculate the final volume of the solution

The final volume is equal to the sum of the volumes of the initial HCl solution and the volume of distilled water.

V₂ = 100 mL + 100 mL = 200 mL

Step 2: Calculate the final concentration of HCl

We will use the dilution rule.

C₁ × V₁ = C₂ × V₂

C₂ = C₁ × V₁/V₂ = 0.002 M × 100 mL/200 mL = 0.001 M

Step 3: Calculate the pH of the final HCl solution

Since HCl is a strong acid, [H⁺] = HCl. We will use the definition of pH.

pH = -log [H⁺] = -log 0.001 = 3

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.