Water Analysis Part 6 Flashcards
What does the acronym SPANA stand for?
Compounds of sodium, potassium , ammonium, nitrate and acetate are always soluble
What does the acronym CHOPS stand for?
Compounds of carbonate, hydroxide, oxide, phosphate and sulphide are insoluble unless combined with SPANA ions
What is the solubility of a substance dependent on?
Temperature
What does the solubility curve show?
The number of grams of solute in a saturated solution of 100g of water at a certain temperature
What are solutes whose curves move upward with increased temperature?
Solids, because the solubility of solids increases with increased temperature
What are solutes whose curves move downward with increased temperature?
Gases, because the solubility of gases decreases with increased temperature
What does any amount of solute below the line indicate?
The solution is unsaturated at a certain temperature
What does any amount of solute above the line in which all of the solute has dissolved show?
The solution is supersaturated at a certain temperature
How do you find the number of grams needed to saturate a solution when the volume is not 100mL?
Volume x Solubility / 100mL
What does seawater contain and what is the most common substance found in it?
Considerable amounts of dissolved salts, most common substance is chloride
Why does water obtained from deep wells have more dissolved solids than rainwater?
Other solids are dissolved in it before it reachers where humans can access it, whereas rainwater comes straight from the sky to the ground
When two solutions are mixed, what may be observed?
An insoluble white or coloured precipitate
Where does the precipitate go in the solution?
It can sink to the bottom or remain suspended in solution
When do precipitation reactions occur?
When two soluble compounds are mixed to form an insoluble product and an exchange of ions happens
When will a precipitation reaction not occur?
If no combinations of cations and anions mixed produce an insoluble substance
