Determing the Empirical Formula of Silver Oxide

Calculations

Con't

Calculations

Basic Laboratory Setting

Silver Oxide prior to experimentation

Material Safety Data Sheet

Make sure all chemical(s) used are studied prior to their use in the laboratory. The MSDS is research and recorded into the designated area and all precautions are taken to keep the environment safe and productive.

Silver metal after experiementation

Silver Oxide:

Health Effects: Hazardous in case of skin contact, eye contact, ingestion, or inhalation.

First Aid:

-Eye Contact: Rinse eyes with eye wash station and nurse/ instructor is to be notified

-Skin Contact: Wash immediately with plenty of water and non-abrasive soap. Be careful to clean folds and seek medical attention

Stability:

The product is stable and non-corrosive in the presence of glass.

Discussion of Theory

Law of Definite Proportions

& Percent Composition usage

What do the calculations show?

By this law, atoms and molecules must react in whole number ratios. The number of moles of each element reacted in whole number ratios. For every 2 moles of silver, 1 mole of oxygen was found in the composition of silver oxide.

The percentage of composition corresponds with this ideal as well because for a certain sample of silver oxide, a definite percentage of the sample will be of silver while the other definite percentage is for oxygen.

The calculations show the empirical formula of Ag2O, Each trial proved an Ag to O ratio of 2 to 1 which is used to write the empirical formula. An empirical formula describes the composition of a compound in terms of the simplest whole number ratio. Empirical means experimentally determined, so the determination of the percent composition is used to unearth the empirical formula, in this case Ag2O.

Law of Conservation of Mass

Conclusion

How was the purpose of the lab fulfilled?

According to this the mass at the start of the equation is equal to the mass at the end of the equation. Due to this, it if is inferred that the grams of silver at the end of the reaction are equal to the grams of silver at the end of the reaction. The total mass of the crucible is different because the oxygen is escaping as it converts to a gas.

The procedure, when fully executed, gave the lab's purpose its full embodiment. The purpose of trying to find the empirical formula of silver oxide was thus fulfilled. The chemistry fundamental concepts, when used in unison, aided the building of purpose. Thus, the purpose was completed by the proper use of a decomposition reactions and the study of practical applications of the law of definite proportions and the law of conservation of mass.

Mass of Silver Oxide and silver metal

Usage of Law of Conservation

Percent Composition of silver and oxygen in silver oxide

Determining the Empirical Formula of Silver Oxide

Experimental Sources of Error

Calculate moles of silver and oxygen in the products

Using molar masses

Data Results Table

Find the Empirical Formula of silver oxide

Theoretical Yield

&

Percent Yield

Sources of Error

And its effect on the Percent Yield

Refer to Slide 23 for the Experimental sources of error

This includes the percent error calculations, the effects of certain mistakes in the lab on the percent yield, and how to correct mistakes of accuracy and precision. (If the experiment were to be reconducted)

(3-4 slides following that will be the calculations of the percent error)

Balanced chemical equation of the decomposition of silver oxide:

2Ag2O O2 + 4Ag

Post Lab Questions

Many events could have happened to hinder or alter the final outcome of the lab. Sources of error in this experiment included those that would cause the yield to be less than 100%, and those that would cause the yield to appear to be more than 100%.

If the crucible is heated to rapidly there can be loss of product due to spattering. This would be evident as silvery flecks would collect on the table around the crucible. The mass of the silver would seem less and give a lower percentage.

Another error source would involve not allowing enough heating of the crucible prior to measuring its mass at the beginning. Heating the crucible drives off any water that may have condensed on the crucible during storage. This is not a easily visible concept at the start but is very likely since there is always water vapor in the air and most lab equipment is stored in a closet with low ventilation. Water vapor or any other volatile adhered to the crucible will cause the empty crucible mass to be higher. When the silver oxide is heated, the oxygen as well as the volatiles will be driven off, making the mass of oxygen driven off appear higher than it actually is. The ratio of silver to oxygen will be closer to a 1:1 ratio given the wrong empirical formula. Since it would appear as though there was less silver compared to the original mass, this would reduced the numerator in the percent yield equation to give a lower percent yield.

On the other hand, if incomplete decomposition of the silver oxide occurred because the crucible with the silver oxide was not heated enough, then they amount of the oxygen taken would be lower making it appear as though there was a higher amount of silver than reality. So the percent yield would be over

Percent Error

From this experiment we can conclude that the Silver Oxide that was burned had an empirical formula of Ag2O. Such a conclusion was reached through the usage of concepts such as the law of conservation of mass, the law of definite proportions, and empirical formulas.

Performed:

September 26th, 2014

Purpose:

The purpose of this lab was to find the empirical formula of silver oxide. It could be determined by decomposing the silver oxide. By then stoichiometry can be applied to solve for the empirical formula. A real life implication of this lab could be used to determine the empirical formula for other compounds.

Procedure:

Within this experiment, the instruments of the crucible and lid are measured with and without 0.5 grams of silver oxide. Then silver oxide is heat within the crucible with care and a time duration of roughly 20 minutes, or until the oxygen is completely evaporated into its gaseous state. The equipment is allowed to cool. Finally, the mass of the crucible, lid, and the remaining silver metal is recorded using a digital balance. Experiment is conducted a total of three times.

Data

Masses and appearance of product were recorded in the duration of the experiment.

Determining the Empirical Formula of Silver Oxide

Laboratory Experiment

Trial #1 Trial #2 Trial #3

45.751 g

34.9305 g

27.9621 g

Mass of crucible and lid, g

46.2543 g

Materials

35.4422 g

28.4691 g

Mass of crucible, lid, and silver oxide, g

46.2161 g

Silver oxide, 1.5 g

Electronic balance

Bunsen burner

Clay pipestem triangle

Crucible and crucible lid, 15 or 30-mL

Crucible tongs

Ring stand and ring clamp

Wire gauze with ceramic center

35.4202 g

28.4301 g

Mass of crucible, lid, and silver metal, g

White product with various small holes

Basic Equipment Visual (This is not all of the materials)

White product with only a few holes

White product with holes

Appearance of product

silver oxide

By: Saloni Patel

Dhruv Patel

Aakash Patel

Heena Shaikh

Determining the Empirical Formula of Silver Oxide