Here are the answers to the study guide on Acids and Bases.
Part 1: Properties of Acids and Bases
1.
acid
* *Reasoning:* Acids turn blue litmus paper red. Bases turn red litmus paper blue. This is a classic acid property.
2.
acid
* *Reasoning:* Acids react with active metals (like magnesium or zinc) to produce hydrogen gas. Bases generally do not do this.
3.
acid
* *Reasoning:* By definition, an acidic solution has a higher concentration of hydrogen ions ($H^+$) than hydroxide ions ($OH^-$).
4.
base
* *Reasoning:* Bases feel slippery or soapy to the touch (like soap or bleach). Acids feel like water or sting if they are strong.
5.
acid
* *Reasoning:* Acids react with carbonates (like baking soda) to produce carbon dioxide gas, water, and a salt.
6.
acid
* *Reasoning:* Acids often feel rough or can cause burns/corrosion. Bases feel slippery. "Rough" is a property associated with the corrosive nature of acids in this context.
7.
neither
* *Reasoning:* Equal numbers of hydrogen and hydroxide ions describe a neutral substance (like pure water), not an acid or a base.
8.
base
* *Reasoning:* Bases taste bitter (like soap or unsweetened cocoa). Acids taste sour.
9.
acid
* *Reasoning:* Acids taste sour (like lemons or vinegar).
Part 2: Models of Acids and Bases
*Word Bank:* Arrhenius, conjugate base, hydrogen, conjugate acid, hydroxide, Brønsted-Lowry
(10) Arrhenius
(11) hydrogen
(12) hydroxide
(13) hydroxide
* *Reasoning:* The Arrhenius model is the simplest one. It says acids contain hydrogen and produce $H^+$ ions in water, while bases contain hydroxide ($OH^-$) and produce hydroxide ions.
(14) Brønsted-Lowry
(15) hydrogen (or proton)
(16) hydrogen (or proton)
* *Reasoning:* The Brønsted-Lowry model focuses on the transfer of protons (hydrogen ions). An acid donates a proton, and a base accepts a proton.
(17) conjugate acid
(18) conjugate base
* *Reasoning:* In a Brønsted-Lowry reaction, when an acid donates a proton, what is left behind is called its "conjugate base." When a base accepts a proton, it becomes its "conjugate acid."
Final Answer:
Part 1
1. acid
2. acid
3. acid
4. base
5. acid
6. acid
7. neither
8. base
9. acid
Part 2
(10) Arrhenius
(11) hydrogen
(12) hydroxide
(13) hydroxide
(14) Brønsted-Lowry
(15) hydrogen
(16) hydrogen
(17) conjugate acid
(18) conjugate base
Parent Tip: Review the logic above to help your child master the concept of renforcement acids bases and salts worksheet section 3.
