CHEM 1110 Midterm: Chemistry 1110 2007 Fall Test 2
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Observations In columns 3 and 4, record the color and intensity seen. In columns 5 and 6, determine if the substance is an acid or a base, and if the substance is ionic. For the last column, determine which chemical species is acting as an acid or base.
| Data Table 1: Acids and Bases Acting in Water | ||||||
| Well | Substance | 1drop BTB | Plus 1 drop of substance | Acid or base (Q1) | Ionic? Y/N (Q2) | Species acting as acid or base (Q3) |
| 1 | NaHCO3 | |||||
| 2 | CH3COOH | |||||
| 3 | HCL | |||||
| 4 | Na2CO3 | |||||
| 5 | H2SO4 | |||||
| 6 | CH3COONa | |||||
| 7 | NaOH | |||||
| 8 | HNO3 | |||||
| 9 | NaHSO4 | |||||
| 10 | NH3 | |||||
| 11 | H3PO4 | |||||
| 12 | NaH2PO4 | |||||
| 13 | Na2HPO4 | |||||
| 14 | Na3PO4 | |||||
| 15 | NaHSO3 | |||||
| Data Table 2: Following Acid/Base neutralization reactions | ||||||
| Well # | 1 Drop of Each | Observation | +2 Drops Acid | Observation | +2 Drops Base | Observation |
| 1 | BPB + NaOH | HCl | NaOH | |||
| 2 | BPB + NaOH | H2SO4 | NaOH | |||
| 3 | BPB + NaOH | CH3COOH | NaOH | |||
| 4 | BPB + NaOH | H3PO4 | NaOH | |||
| 5 | BPB + Ca(OH)2 | HCl | Ca(OH)2 | |||
| 6 | BPB + Ca(OH)2 | H2SO4 | Ca(OH)2 | |||
| 7 | BPB + Ca(OH)2 | CH3COOH | Ca(OH)2 | |||
| 8 | BPB + Ca(OH)2 | H3PO4 | Ca(OH)2 | |||
| 9 | BPB + NH3 | HCl | NH3 | |||
| 10 | BPB + NH3 | H2SO4 | NH3 | |||
| 11 | BPB + NH3 | CH3COOH | NH3 | |||
| 12 | BPB + NH3 | H3PO4 | NH3 | |||
Please note here if any of the other starting materials is other than a clear, colorless solution.
| Data Table 3: Investigating Odor as a Means of Indicating Neutralization. | |
| Substance(s) | Odor |
| 2 Drops of HCl in Well #1 | |
| 1 Drop of Ammonia on Swab | |
| Swab with Ammonia & HCl | |
| Data Table 4: Investigating Evaporation as a Means of Indicating a Neutralization Reaction. | ||
| Reaction Mixture | Observation (When Wet) | Observation (When Dry) |
| HCl + NaOH | ||
| CH3COOH + NH3 | ||
| HNO3 + NaOH | ||
PART 5: Mini-Experiments
1. Use BTB to classify four household products as acidic or basic. Possible substances to test include home cleaning products, glass cleaner, liquid detergent, bleach, soft drinks, liquid from food items, etc. Remember to:
a. Hypothesis (What you think will happen and why) or purpose:
b. Method used to test your hypothesis:
c. Data and Observations Put your data and observations in the space below. You can include pictures that you âdraw.â
d. Conclusions
2. Find one common, highly colored substance that can be used as an acid-base indicator.
Possible substances include fruit/vegetable juice or products, inks, food coloring, flower
petals, etc. If using fresh fruit, veggies, or flowers, crush the substance with a little water or
rubbing alcohol to extract the colored pigments. If red cabbage is available, it makes a superb
acid-base indicator. Then use a few drops of the colored extract as the indicator. Test four
more household products using the freshly made acid-base indicator. Remember to:
a. State a hypothesis or purpose.
b. State the testing method.
c. Use the prepared indicator to test four substances known to be acids or bases from either the LabPaq or home materials and record results.
d. State conclusions in terms of the hypothesis or purpose.
Questions
A. Review the substances used in Part 1. Determine whether each substance contains an acid or a base based on the BTB results. Place answers to this question in column 6 of Data Table 1.
B. Review the responses to Question 3. The anion that is produced in the dissociation of the compound goes on to react with the water. Identify the anion product in each reaction. Place the formulas for these species into column 7 of Data Table 1. If the substance is not ionic and thus does not dissociate, then list the substance in column 7, just as it appears in column 1.
|
C. For each ionic species in Data Table 1, write the equation showing the dissociation of the compound in water. Hint: thereâs one for each line provided below.
|
a. NaHCO3 Ã Na
+ HCO3
Review the responses to Question 3. The anion that is produced in the dissociation of the compound goes on to react with the water. Identify the anion product in each reaction. Place the formulas for these species into column 7 of Data Table 1. If the substance is not ionic and thus does not dissociate, then list the substance in column 7, just as it appears in column 1.
D. Write the reaction of each acid or base the substance listed in column 7 with water.
Acids: Bases:
a) HCO - + H-OH Ã H CO
+ OH-
3 2 3
1. What is produced in each and every reaction of an acid with water?
2. What is produced in each and every reaction of a base with water?
E. Review the results in Data Table 2. For each reaction mixture, write the reaction equation describing the acid/base neutralization reaction:
2) 2NaOH + H2SO4 Ã 2H2O + Na2SO4
F. Define the term âneutralizationâ and provide an example of a neutralization equation. List the three ways used in this lab to detected neutralization.
G. Define the term âsalt,â and provide an example.
H. Review Data Table 3. What happened when the two chemicals were mixed? What indicates that conclusion? What reaction took place?
I. Review Data Table 4. What happened when the solution mixtures on the glass slide were heated? Describe the process that took place.
J. In Part 4, for HCl + NaOH, what is left on the slide after heating? Provide the formula. What is the common name of this substance?