Vocabulary
What two parts make up a solution?
solute and solvent
True or False. Contaminants in water are always chemicals.
False.
Cup A has 2 grams of copper chloride dissolved in 50 mL of water. What is the solvent?
water
According to the pH scale, what is the range of pH for a basic solution?
> 7
True or False. If equal volumes of an acid and a base are added together, then the pH of the solution will be neutral.
False
What is the cloudiness of a liquid caused by very small particles that are suspended in the liquid called?
turbidity
True or False. Surface water is the only type of water that can become contaminated.
False.
Some salt, vegetables, and spices are added to some hot water. The salt disappears into the water, the vegetables sink, and the spices float. Which is the solute in this mixture?
salt
A cleaning solution of ammonia in water turns universal indicator blue. What can you conclude about ammonia?
it is a base
Give two examples of an everyday solution that is an acid.
(answers will vary) eg. vinegar, lemon juice, orange juice, coke
What is a substance that separates into ions in solution and is capable of conducting electricity?
electrolyte
What two step process is a good way to remove visual water contaminants from a water supply?
coagulation and filtration
Cup A contains 10 g of salt in 100 ml of water, and cup B contains 2 g of salt in 100 ml of water. The salt in both cups is completely dissolved. Which solution is more diluted?
cup B
Any substance that increases the concentration of H+ ions when it dissolves in water is ___________
an acid
Any substance that increases the concentration of OH- ions when it dissolves in water is ___________
a base
What is the ability of a solute to dissolve in a solvent?
solubility
If the pH of a water sample is 7, then is the water safe to drink?
not necessarily. The pH level is safe, but what about the other federal standards for water safety.
Why is water known as the universal solvent?
because it dissolves many other substances
Can a base conduct electricity? Explain.
Yes, if mixed in water, the ions of the base will separate allowing electrical conductivity.
In the lab, Matisse uses hydrochloric acid (HCl) to neutralize sodium hydroxide (NaOH). Write the chemical equation that illustrates this reaction.
HCl+ NaOH ----> H2O + NaCl
What is the difference between an ionic and a covalent bond?
In a covalent bond, the electrons are shared by two atoms. In an ionic bond, the electrons are transferred from one atom to another.
What are the six areas of Federal Standards for water quality?
turbidity, odor, pH, iron, nitrates, copper
Cup 1 in the tray below has a solution that is 1 part salt per 1000 parts of water. One drop of solution is taken from cup 1 and added to 9 drops of water in cup 2, and this process is repeated until all cups are filled. Which cup will contain a solution that is 1 ppm of salt? Explain your reasoning.
cup 4
In a serial dilution, each cup gets diluted by a factor of 10. Cup 1 starts out as 1/1000, so it has to be diluted x 1/10 x 1/10 x 1/10 in order to reach 1/1,000,000 (which is 1 ppm)
Name two similarities between acids and bases AND two differences.
(Answers may vary)
similarities = both are not neutral; both can be be harmful / corrosive; both can conduct electricity
differences - Acids have pH < 7 and Bases have pH > 7; Acids are sour and Bases are bitter; Acids have H+ ions while bases have OH- ions.
Is the ability of an acid and a base to neutralize each other a chemical property or a physical property. Explain using examples from this unit.
A neutralization reaction is the result of the chemical properties of acids and bases. When these two substances interact, they produce a new substance. The evidence is that the neutral solution reacts differently with an indicator to produce a different color than either the acidic or basic solution.