Week 3&4: Reading 4a to 4d

Question 1

How is mg/L converted to meq/L? for elements

Answer 1

mg/L x (valence/atomic weight)

Question 2

How is mg/L converted to meq/L for radicals/compounds?

Answer 2

mg/L x (e- charge/molecular weight)

Question 3

What are chemical reactions in water and wastewater treatment used for?

Answer 3

They are used to shift the chemical equilibria in order to remove substances from the water

Question 4

What are the most common ways to strip unwanted substances via chemical reactions?

Answer 4

• Precipitation reactions
• Oxidation and Reduction Reactions
• Acid-Base Reactions
• Gas-producing Reactions

Question 5

What is the difference between oxidation and reduction?

Answer 5

Oxidation is the addition of oxygen or removal of electrons

Reduction is the removal of oxygen or addition of electrons
(Think REduction - REmoval of oxygen)

Question 6

How are zero, first and second order kinetics defined?

Answer 6

Zero-order: reactions proceed at rate independent of concentration of reactant or product

First-order: reactions proceed at rate directly proportional to concentration of one reactant.

Second-order: reactions proceed at rate proportional to second power of a single reactant being converted to a single product

Question 7

What order of reaction is most common in water and wastewater?

Answer 7

First order

Question 8

Generally, what does increasing temperature do to the rate of chemical reactions?

Answer 8

It increases the rate of reaction