Question

hypothesis (6 pts.)
\sodium bicarbonate is added to calcium chloride and phenol red
then it will cause an exothermic reaction
or physical change
because heat will leave the chemicals
or change

materials (for each trial):

• calcium chloride
• sodium bicarbonate
• phenol red solution
• ziplock bag
• scale
• graduated cylinder (10 - ml)
• weighing dish (x2)

table i (10 pts.)
qualitative data (minimum of 2 each)
calcium chloride: white and round
sodium bicarbonate: powder - like and white
phenol red: liquid, red
what happens when chemical are mixed?: bubble, change color

experimental procedure:

1. use 2 different weighing boats to keep chemicals apart (calcium chloride, sodium bicarbonate)
2. measure the mass of a scoop of both solids and record the masses in table ii
3. measure the mass of 5 ml of phenol red solution and record mass in table ii
4. measure the mass of the empty ziplock bag and record mass in table ii
5. place all three substances into the ziploc bag without letting them touch and seal the bag. once the bag is sealed, mix the substances together and record any observations you make in table i.
6. when the mixing has been completed, measure the mass of everything by placing the still - sealed ziploc bag on the scale. record the mass in table ii.
7. repeat steps 1 - 7 to complete all of your trials

table ii (32 pts.)
quantitative data
trial 1 | trial 2 | trial 3 | average
mass of calcium chloride: 1.33 | 0.69 | 1.32 | 1.11
mass of sodium bicarbonate: 1.35 | 1.00 | 1.64 | 1.33
mass of phenol red: 1.9 | 1.81 | 2.54 | 2.08
mass of ziploc bag: 2.41 | 2.53 | 2.56 | 2.50
total mass before mixing: 7.00 | 6.83 | 8.04 | 7.02
total mass after mixing: 6.19 | 5.32 | 6.85 | 6.12
change in mass: 0.81 | 0.71 | 1.19 | 0.90
was mass conserved?: no | no | no | no

Explanation:

To determine the average values for each row in Table II, we use the formula for the average (mean) of a set of numbers:

\[
\text{Average} = \frac{\text{Sum of values}}{\text{Number of values}}
\]

Since there are 3 trials, the number of values is 3 for each row.

1. Average Mass of Calcium Chloride

The masses for Calcium Chloride in Trial 1, Trial 2, and Trial 3 are \( 1.33 \), \( 0.69 \), and \( 1.32 \) respectively.

\[
\text{Sum} = 1.33 + 0.69 + 1.32 = 3.34
\]
\[
\text{Average} = \frac{3.34}{3} \approx 1.11
\]

2. Average Mass of Sodium Bicarbonate

The masses for Sodium Bicarbonate in Trial 1, Trial 2, and Trial 3 are \( 1.35 \), \( 1.00 \), and \( 1.64 \) respectively.

\[
\text{Sum} = 1.35 + 1.00 + 1.64 = 3.99
\]
\[
\text{Average} = \frac{3.99}{3} = 1.33
\]

3. Average Mass of Phenol Red

The masses for Phenol Red in Trial 1, Trial 2, and Trial 3 are \( 1.9 \), \( 1.81 \), and \( 2.54 \) respectively.

\[
\text{Sum} = 1.9 + 1.81 + 2.54 = 6.25
\]
\[
\text{Average} = \frac{6.25}{3} \approx 2.08
\]

4. Average Mass of Ziploc Bag

The masses for Ziploc Bag in Trial 1, Trial 2, and Trial 3 are \( 2.41 \), \( 2.53 \), and \( 2.56 \) respectively.

\[
\text{Sum} = 2.41 + 2.53 + 2.56 = 7.50
\]
\[
\text{Average} = \frac{7.50}{3} = 2.50
\]

5. Average Total Mass Before Mixing

The total masses before mixing in Trial 1, Trial 2, and Trial 3 are \( 7.00 \), \( 6.83 \), and \( 8.04 \) respectively.

\[
\text{Sum} = 7.00 + 6.83 + 8.04 = 21.87
\]
\[
\text{Average} = \frac{21.87}{3} = 7.29 \quad (\text{Note: The handwritten average of } 7.02 \text{ may be incorrect; recalculated here.})
\]

6. Average Total Mass After Mixing

The total masses after mixing in Trial 1, Trial 2, and Trial 3 are \( 6.19 \), \( 5.32 \), and \( 6.85 \) respectively.

\[
\text{Sum} = 6.19 + 5.32 + 6.85 = 18.36
\]
\[
\text{Average} = \frac{18.36}{3} = 6.12
\]

7. Average Change in Mass

The change in masses in Trial 1, Trial 2, and Trial 3 are \( 0.81 \), \( 0.71 \), and \( 1.19 \) respectively.

\[
\text{Sum} = 0.81 + 0.71 + 1.19 = 2.71
\]
\[
\text{Average} = \frac{2.71}{3} \approx 0.90
\]

8. Was Mass Conserved?

For each trial, the total mass after mixing is less than before mixing (e.g., Trial 1: \( 6.19 < 7.00 \); Trial 2: \( 5.32 < 6.83 \); Trial 3: \( 6.85 < 8.04 \)). Thus, mass was not conserved in any trial, so the average (and all trials) answer is "No."

Final Table II (with corrected average for Total Mass Before Mixing)

Quantity	Trial 1	Trial 2	Trial 3	Average
Mass of Sodium Bicarbonate	\( 1.35 \)	\( 1.00 \)	\( 1.64 \)	\( 1.33 \)
Mass of Phenol Red	\( 1.9 \)	\( 1.81 \)	\( 2.54 \)	\( 2.08 \)
Mass of Ziploc Bag	\( 2.41 \)	\( 2.53 \)	\( 2.56 \)	\( 2.50 \)
Total Mass Before Mixing	\( 7.00 \)	\( 6.83 \)	\( 8.04 \)	\( 7.29 \)
Total Mass After Mixing	\( 6.19 \)	\( 5.32 \)	\( 6.85 \)	\( 6.12 \)
Change in Mass	\( 0.81 \)	\( 0.71 \)	\( 1.19 \)	\( 0.90 \)
Was Mass Conserved?	No	No	No	No

(Note: The handwritten average for "Total Mass Before Mixing" was \( 7.02 \), but recalculation shows \( 7.29 \). This discrepancy may be due to rounding or calculation errors in the original data.)

Answer:

To determine the average values for each row in Table II, we use the formula for the average (mean) of a set of numbers:

\[
\text{Average} = \frac{\text{Sum of values}}{\text{Number of values}}
\]

Since there are 3 trials, the number of values is 3 for each row.

1. Average Mass of Calcium Chloride

The masses for Calcium Chloride in Trial 1, Trial 2, and Trial 3 are \( 1.33 \), \( 0.69 \), and \( 1.32 \) respectively.

\[
\text{Sum} = 1.33 + 0.69 + 1.32 = 3.34
\]
\[
\text{Average} = \frac{3.34}{3} \approx 1.11
\]

2. Average Mass of Sodium Bicarbonate

The masses for Sodium Bicarbonate in Trial 1, Trial 2, and Trial 3 are \( 1.35 \), \( 1.00 \), and \( 1.64 \) respectively.

\[
\text{Sum} = 1.35 + 1.00 + 1.64 = 3.99
\]
\[
\text{Average} = \frac{3.99}{3} = 1.33
\]

3. Average Mass of Phenol Red

The masses for Phenol Red in Trial 1, Trial 2, and Trial 3 are \( 1.9 \), \( 1.81 \), and \( 2.54 \) respectively.

\[
\text{Sum} = 1.9 + 1.81 + 2.54 = 6.25
\]
\[
\text{Average} = \frac{6.25}{3} \approx 2.08
\]

4. Average Mass of Ziploc Bag

The masses for Ziploc Bag in Trial 1, Trial 2, and Trial 3 are \( 2.41 \), \( 2.53 \), and \( 2.56 \) respectively.

\[
\text{Sum} = 2.41 + 2.53 + 2.56 = 7.50
\]
\[
\text{Average} = \frac{7.50}{3} = 2.50
\]

5. Average Total Mass Before Mixing

The total masses before mixing in Trial 1, Trial 2, and Trial 3 are \( 7.00 \), \( 6.83 \), and \( 8.04 \) respectively.

\[
\text{Sum} = 7.00 + 6.83 + 8.04 = 21.87
\]
\[
\text{Average} = \frac{21.87}{3} = 7.29 \quad (\text{Note: The handwritten average of } 7.02 \text{ may be incorrect; recalculated here.})
\]

6. Average Total Mass After Mixing

The total masses after mixing in Trial 1, Trial 2, and Trial 3 are \( 6.19 \), \( 5.32 \), and \( 6.85 \) respectively.

\[
\text{Sum} = 6.19 + 5.32 + 6.85 = 18.36
\]
\[
\text{Average} = \frac{18.36}{3} = 6.12
\]

7. Average Change in Mass

The change in masses in Trial 1, Trial 2, and Trial 3 are \( 0.81 \), \( 0.71 \), and \( 1.19 \) respectively.

\[
\text{Sum} = 0.81 + 0.71 + 1.19 = 2.71
\]
\[
\text{Average} = \frac{2.71}{3} \approx 0.90
\]

8. Was Mass Conserved?

For each trial, the total mass after mixing is less than before mixing (e.g., Trial 1: \( 6.19 < 7.00 \); Trial 2: \( 5.32 < 6.83 \); Trial 3: \( 6.85 < 8.04 \)). Thus, mass was not conserved in any trial, so the average (and all trials) answer is "No."

Final Table II (with corrected average for Total Mass Before Mixing)

Quantity	Trial 1	Trial 2	Trial 3	Average
Mass of Sodium Bicarbonate	\( 1.35 \)	\( 1.00 \)	\( 1.64 \)	\( 1.33 \)
Mass of Phenol Red	\( 1.9 \)	\( 1.81 \)	\( 2.54 \)	\( 2.08 \)
Mass of Ziploc Bag	\( 2.41 \)	\( 2.53 \)	\( 2.56 \)	\( 2.50 \)
Total Mass Before Mixing	\( 7.00 \)	\( 6.83 \)	\( 8.04 \)	\( 7.29 \)
Total Mass After Mixing	\( 6.19 \)	\( 5.32 \)	\( 6.85 \)	\( 6.12 \)
Change in Mass	\( 0.81 \)	\( 0.71 \)	\( 1.19 \)	\( 0.90 \)
Was Mass Conserved?	No	No	No	No

(Note: The handwritten average for "Total Mass Before Mixing" was \( 7.02 \), but recalculation shows \( 7.29 \). This discrepancy may be due to rounding or calculation errors in the original data.)