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Lab Instructor: Date: Lab Section: Acid and Alkali Content of Consumer Products

ID: 555673 • Letter: L

Question

Lab Instructor: Date: Lab Section: Acid and Alkali Content of Consumer Products PRELAB ASSIGNMENT 1. For each product listed, provide the chemical formula and name of the acid or base Label each substance as an acid or a base. Consumer Product Lemon juice Rolaids antacid Tums antacid in that product. Substance Name Substance Formula Acid or Base? In Part 1, you will use the observed solution color change due to phenolphthalein (colorless to pink, at the endpoint) to indicate the completion of each reaction. Due to the colors of the juices you will be studying, the expected color change of colorless to pink may not be observed. For each juice, state the color change that you will observe at the endpoint. 2. Grapefruit juice Orange juice Lemon juice The indicator that will be used in Part 2 is methyl orange. What is the color change that you will observe at the endpoint for the titration of the Rolaids and Tums? 3. The structure and formula of citric acid is provided in the lab writeup. Calculate (show work) the molecular weight of citric acid. 4. 0.09872 M Ba(OH)2 solution to titrate this HCI sample. What is the molarity of the HCI sample? Show all work. 5. A 15.00-mL sample of an HCI solution was titrated with a Ba(OH) solution. It required 10.15 mL of a Ba(OH), + 2 HCI Bac, + 2H20

Explanation / Answer

Q1

a)

Lemon juice --> citric acid

citric acid has the formula --> C6H8O7

this is an ACID, as the name states it, and will donate H+ in solution, pH is < 7

b)

Rolaids antacid --> Calcium carbonate ad Magnesium Hydroxide

Formulas --> CaCO3(s) and Mg(OH)2 mainly

these are basics, since will decrease [H+] in solution and increases [OH-] therefore pH >7

c)

Tums antacid are mainly CaCO3(s) and MgCO3(s)

name are calcium carbonate and magnesium carbonate

these are bases, since they will decrease [H+] increase [OH-] and ph >7