48 Mixing an Acid and a Base

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48 Mixing an Acid and a Base

Key Vocabulary

• acid• base• concentration• model• molecule• neutral• neutralize, neutralization• pH

48 Mixing an Acid and a Base

What do you predict will happen to pH when an acid and a base are mixed together?

Record your answer in your notebook.

48 Mixing an Acid and a Base

Read the introduction and look for key ideas

48 Mixing an Acid and a Base

What happens when you mix an acid and a base?

Orange juice is acidic.

48 Mixing an Acid and a Base

Complete procedure Part A: Mixing an Acid and a Base: Qualitative Observations.

Record your data in your notebook.

48 Mixing an Acid and a Base

What happens to the concentration of ions in the mixture as it becomes more basic?

Discuss your thoughts with the class.

48 Mixing an Acid and a Base

What happens as the hydroxide ion concentration continues to increase as more base is added?

Discuss your thoughts with the class.

48 Mixing an Acid and a Base

Complete procedure Part B: Mixing an Acid and a Base: Quantitative Observations.

Record your results in your notebook.

48 Mixing an Acid and a Base

Class results

48 Mixing an Acid and a Base

What are possible reasons for the different results for each neutralization?

Share your thoughts with the class.

48 Mixing an Acid and a Base

Analysis question 1

What happens as you add an acid to a basic solution or add a base to an acidic solution?

48 Mixing an Acid and a Base

What do you think is happening to make the solutions become neutral?

Do you think one drop of the acid you used and one drop of the base have equal numbers of particles? What do you think happened to the acid and base particles when they were mixed?

Discuss your thoughts with the class.

48 Mixing an Acid and a Base

Analysis question 2

Which solution seems more powerful in this investigation, the acidic or the basic? Explain your answer.

48 Mixing an Acid and a Base

Analysis question 3

Based on what you know so far, which do you think is a better way of neutralizing an acid: diluting it with water, or adding a base? Explainyour answer.

48 Mixing an Acid and a Base

Analysis question 4

Given two solutions, how might you determine:

a. whether these solutions are acidic or basic?

b. which is more acidic or basic?

48 Mixing an Acid and a Base

What happens when you mix an acid and a base?

48 Mixing an Acid and a Base

Key vocabulary definitions

Acid - A material that acts as if it were the opposite of a base in a reaction. Acids taste sour and are usually very corrosive (destructive to metal or flesh). A strong acid has a pH below 1 on the pH scale. Some strong acids are nitric, sulfuric, and hydrochloric acids.

48 Mixing an Acid and a Base

Key vocabulary definitions

Base - A substance that acts in an opposite way to an acid in a reaction. Bases taste bitter and are usually corrosive. Some strong bases include sodium hydroxide (lye) and chlorine bleach. Bases have a pH higher than 7.

48 Mixing an Acid and a Base

Key vocabulary definitions

Concentration - The quantity of a particular type of matter that exists in a unit volume. The more of that type of matter present per unit volume, the more concentrated the substance. In a solution, it is the amount of solute per unit of solution; therefore, the more solute per solventthat is present, the more concentrated the solution.

48 Mixing an Acid and a Base

Key vocabulary definition

Model - Something that is used to describe a larger or smaller object; a description of an event or object that accounts for all its properties.

Molecule - The smallest particle of an element or compound that displays the properties of the substance in quantity.

48 Mixing an Acid and a Base

Key vocabulary definitions

Neutral - A solution that has a pH of 7. It is neither an acid or a base.

Neutralization - A balance of acid and base so that their particles (molecules) are present in equal amounts. The products of neutralization are water and a salt. When an acid is neutralized by a base, the resulting solution is said to be neutral and has a pH of 7.

48 Mixing an Acid and a Base

Key vocabulary definitions

pH - A way of describing the acidic or basic strength of a solution. The pH value of a solution is a number on a scale from 0 to 14. A pH value of 0–1 indicates a strong acid. A pH value of 12–14 indicates a strong base. A pH value of 7 indicates a neutral solution.