Law of Conservation of Mass (Incomplete)

Law of Conservation of Mass

Keyword – chemical reaction, reactants, conservation of mass, percentage error, neutralization.

I. INTRODUCTION

II.OBJECTIVES

By the end of the experiment, the experimenter should be able to:

·         Verify and observe the Law of Conservation of Mass.

·         Observe and identify indicators of a chemical reaction.

III. HYPOTHESIS

The total mass of the reactants is equal to the mass of the products.

IV. METHODOLOGY

A. Materials

·         Chemical

Ø  Vinegar

·         Laboratory Materials

Ø  10 mL Graduated Cylinder

Ø  250 mL Erlenmyer Flask

Ø  600 mL Beaker

Ø  Analytical Balance

Ø  Funnel

·         Other Materials

Ø  2 L Soda Bottle

Ø  2 Medium Sized Balloons

Ø  Baking Soda

Ø  Newspapers

B. Experimental Procedures

·         Trial #1

Ø  First, measure and record the mass of the empty beaker using the analytical balance. Once done, using the graduated cylinder measure and pour about 30 mL of vinegar into the beaker, then weigh and record the mass of the beaker and vinegar.

Ø  Using the analytical balance weigh 5 g of baking soda onto a piece of newspaper and record the exact mass of baking soda used.

Ø  Place the beaker with vinegar and the paper with baking soda on the analytical  balance, then measure and record the mass of the reactants in their respective containers.

Ø  Pour  the baking soda into the beaker with vinegar and let the chemical reaction finish. Once it completes, Using the analytical balance, measure and record the mass of the reactants’ products.

·         Trial #2

Ø  Measure and record the mass of the empty 2 L soda bottle. After that, using the graduated cylinder measure about 30 mL of vinegar and pour it into the empty soda bottle through a funnel. Once finished, obtain the mass of the soda bottle with vinegar and then record it.

Ø  Weigh 5 g of baking soda onto a piece of newspaper using the analytical balance and record the exact mass of the baking soda along with the soda bottle that contains the vinegar.

Ø  Tilt the 2 L soda bottle with vinegar and insert the 5 g of baking soda into the neck of the soda bottle and close the cap tightly.

Ø  Tip the 2 L soda bottle upright and allow the chemical reaction between the reactants to complete. When finished, use the analytical balance to measure the mass of the chemical reaction’s products and then record it.

·         Trial #3

Ø  Using the analytical balance, measure and record the mass of the empty flask. Once finished, measure then about 30 mL of vinegar using the graduated cylinder and pour it into the 250 ml erlenmyer flask via a funnel. Obtain the mass of the flask with the vinegar using the analytical balance and record it.

Ø  Using the analytical balance obtain 5 of baking soda unto a piece of newspaper and then measure and record the exact mass of the baking soda and the erlenmyer flask that contains the vinegar. After that, measure the mass of the medium sized balloon.

Ø  Insert the 5 g of baking soda into the medium sized balloon. Slip the open end of the balloon over the mouth of the flask with vinegar without letting the baking soda enter the flask yet.

Ø  Once the open end of the balloon is completely covering the mouth of the flask, tip the balloon upright and allow the chemical reaction to finish. Once the reaction completes, measure and record the mass of the chemical reaction’s products using the analytical balance.

C. Safety Precautions

·         Safety googles and lab aprons must be worn, vinegar is a weak acid.

·         Handle all the laboratory apparatuses with care to avoid breakage.

V. DATA

TABLE I
QUANTITATIVE OBSERVATIONS

Mass	Trials
	1	2	3
Empty Container	213. 0 g	46.5 g	95.0
Container with Vinegar	242.0 g	73.5 g	124.0 g
Vinegar	29.0 g	27.0 g	29.0 g
Baking Soda	5.0 g	5.0 g	5.0 g
Container with Vinegar and Baking Soda	247.0 g	78.5 g	129.0 g
Reactants	34.0 g	32.0 g	34.0 g
Balloon	-	-	3.0 g
Container with Product	246.0 g	77.0 g	128.0 g
Product	33.0 g	30.5 g	33.0 g
Percent Error	2.94%	4.69%	2.94%

TABLE II
QUALITATIVE OBSERVATIONS

	Trial
	1	2	3
Before	The vinegar was in liquid form,
	The baking soda was in solid form, was powdery, and was  white.
After

VI. ANALYSIS AND DISCUSSION

There were two reactants in this experiement, vinegar and baking soda. Vinegar is an acetic acid while baking soda is a bicorbonate or a base. The reaction of these two reactants are called Neutralization.

In Neutralization, an acid, which in this case is vinegar, reacts with a base, baking soda, to produce water, salt, and carbon dioxide.

For all three trials in the experiment, when the baking soda was poured into the beaker, the reactants fizzled, formation of bubbles occured, and carbon dioxide was produced.

The production of carbon dioxide is seen on the first, second, and third trial by the release of a gas, the bloating of the soda bottle, and the inflation of the balloon.

How did the final mass of the system compare with the initial mass of the system for each trial? If the law of conservation of mass was violated, justify your results.

The mass of the product for all three trials were less than the initial mass of the reactants. But hey the mass stayed the same.

Indicate the state of matter for each reactant and product.

How else could you have tested the law of conservation of mass for this reaction? What other experimental designs could you have implemented? Explain your revised procedure.

VII. CONCLUSION

REFERENCES

[1] Helmenstine, T. (2014). Calculate percent error. Retrieved     July 23, 2016, from http://sciencenotes.org/calculate-percent-error/.

[2] Huang, M. (n.d.). Conservation of mass lab (4/5). Retrieved July 23, 2016, from http://madelineisn.weebly.com/conservation-of-mass-lab.html.

[3] The Regents of the University of California. (2015). Why does baking soda and vinegar react to each other?. Retrieved July 23, 2016, from http://scienceline.ucsb.edu/getkey.php?key=4147.

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