Calculation Environmental Fundamentals (20s) Solve the following 4 problems (5%

Question

Calculation Environmental Fundamentals (20s) 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? b) The 86-proof whiskey contains 43% ethyl alcohol (CH_3 CH_2 OH) by volume (density = 0.79 kg/L). What is the concentration of ethyl alcohol (in mg/L) and the theoretical oxygen demand for whiskey? c) 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 1.5%. How long would it take to use up the current reserves? d) Phase Change & Sensible/Latent Heat (5%) - Use Phase Triangle to briefly explain phase change processes. Using an energy-temperature diagram, explain the heating process of arctic ice (mass m, specific heat c_ice, temperature - 30 degree C) being heated by hot Sun to superheated vapor (specific heat. c_steam, temperature 105 degree C) into the sky How much heat from Sun is needed?

Explanation / Answer

Answer: a-

pOH = -log10[OH-]
[OH-] is the concentration of hydroxide ions in mol L-1 (mol/L or M)

[OH-] = 10-pOH

As the pOH decreases, the concentration of hydroxide ions in the solution increases.

=>hydroxide concentration for tomato juice:- pH+pOH =14

4.1 + pOH=14

pOH=9.9

hydroxide ion = 10^ -pOH= 10^ -9.9 = 1.2589254e-10

b- molar mass of ethyl alcohol is= 46.07g

Concentration of whisky= 0.79 kg/L * 0.43 L / 1 L * 1000 g / 1 kg * 1 mol / 46.07 g = 7.37 M

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