Calculations Environmental Fundamentals (208) -- Solve the following 4 problems

Question

Calculations Environmental Fundamentals (208) -- Solve the following 4 problems (5 % each): Use next blank page as needed a) pH-What is hydroxide ion concentration [OH^-] in molarity and in [mg/L] of tomato juice having a ph of 4.1? 86-proof whiskey contains 43% ethyl alcohol (CH_3CH_2OH) by volume (density = 0.79 kg/L) What is the concentration of ethyl alcohol (in mg/L) and the theoretical oxygen demand for whiskey? Resource usage-The world reserves of coal are 1,000 billion tons, and current usage is about 8 billion tons per year with exponential growth rate of 1.58 How long would it take the current reserves? Phase Change Use Phase Triangle to being

Explanation / Answer

I'll report 3 significant figures as requested although the pH for tomato juice given (4.1) has only two.

To calculate [H+],

[H+] = 10^-pH = 10^(-4.1) = 7.94 x 10^-5 M.

Pure water at 25 C has a pH of 7, which is neutral (neither acidic nor basic). The [H+] is 1 x 10^-7. If a solution has an [H+] > 1 x 10^-7, it is acidic. If [H+] < 1 x 10^-7, the solution is basic (alkaline).

The pH scale is logarithmic. A change of one pH unit lower is a 10X increase in acidity.

pH = -log[H+]

If a solution has a pH < 7, it is acidic. If pH > 7, the solution is basic (alkaline). Just remember that as the amount of acid in a substance increases, the pH DECREASES.

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