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The Determination of a Chemical Formula

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❶Remove the first washer and use the stir stick to scrape the copper into the metal cupcake wrapper. Present to your audience.

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Comments 0 Please log in to add your comment. Transcript of The Determination of a Chemical Formula Objective Objective The purpose of this lab was to calculate the empirical formula of a copper chloride compound. We did this by separating the individual elements copper and chlorine and compound water out of the original compound through physical and chemical reactions.

We used the masses of the components of the original compound to compute the subscripts for the empirical formula Procedure We were first handed a copper chloride hydrate.

The first process we had to do complete was the removal of water from the compound. We did this by placing approximately 1 gram 0. Because copper and chloride have much higher melting points than water, only the water evaporated. Procedure cont'd Once the copper chloride had turned from a greenish-blue to a dark brown color, we knew that all of the water had evaporated from the compound. We then measure the dehydrated copper chloride sample.

It had a mass of 0. By subtracting the mass of the hydrated sample from the dehydrated sample, we found the mass of the water that had evaporated. Procedure con't We then placed the 0. The water become green again as the copper chloride dissolved. We then placed a coil of 20 cm of aluminum wire into the solution. We let the reaction occur for 30 minutes.

H O 2 Summary: This broke up the copper from the wire. We got a piece of filter paper that weighed 0. We then place a piece of filter paper inside a funnel and poured the solution into the funnel.

This separated the elemental copper from the rest of the solution. We weighed the filter paper with the copper in it and it weighed 1. We then divided all of the amounts of moles by the smallest amount, which was 0.

This gave us the subscripts for the molecular and technically empirical formula for the copper chloride hydrate compound. Analysis cont'd We got CuCl 2 H 0 for the empirical formula. The correct empirical formula for the copper chloride hydrate is CuCl 2 H 0.

The End Conclusion We concluded that we didn't get the right empirical formula because we did not measure our substances correctly. This could be due to the fact that we didn't directly measure the the amount of chlorine. We subtracted the mass of the dehydrated sample copper chloride from the amount of copper collected to compute the mass of the chlorine.

Add two aluminum washers to the solution. Heat the beaker until solution clears. Your solution may not turn completely clear, but some color change should be evident. Alternatively you can also determine when the reaction is complete by looking for the formation of gas bubbles on the surface of the washers. When the formed gas bubbles are gone, then the reaction is complete. Plastic beakers should never be used with heat. Decant pour the clear liquid into a 50 mL beaker.

When all that remains in the original beaker are the copper plated washers, rinse the washers with distilled water and decant the remaining liquid, being careful not to lose any copper, into a container.

This water can be disposed of down a sink drain. Repeat this process three times. Remove the first washer and use the stir stick to scrape the copper into the metal cupcake wrapper. Rinse the washer with distilled water to be sure all copper is recovered into the wrapper. Repeat the process for the second washer, scraping the copper into the same wrapper. Monitor the wrapper and contents and use a hot pad or towel to carefully remove them from the oven after 45 minutes, or after all of the water has evaporated.

After the wrapper has cooled to room temperature, empty the dried copper from the wrapper onto the scale and weigh the final mass. Create a pie chart showing the percent composition for each element in the compound copper gluconate, clearly label each element and the percentage. Why is it important in this experiment to be accurate in all your measurements? List the measurements you will take in this experiment.


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Lab burner beaker Funnel Filter paper Unknown solid copper chloride hydrate Aluminum wire, 20 gauge 6 M hydrochloric acid, HCL, solution 95% ethanol solution Distilled water Wash bottle Balance Glass stirring rod 5. Remove and turn off the burner. Cover the crucible and allow the sample to cool for about ten minutes. 6.

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In expressing the formula of a hydrated crystal like this one, because the water molecules remain intact, we indicate the number of water molecules incorporated into the crystal (per formula unit) with the nomenclature ⋅zH 2O, rather by than adding H .

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The Determination of a Chemical Formula John Dalton was an Englishman, a teacher, and an exceptional theoretical chemist. He developed and wrote the modern atomic theory at the turn of the 19th century (documents point to ). He was influenced by the experiments of two Frenchmen, Antoine Lavoisier and Joseph Louis Proust. Lab Report #4: Determination of a chemical formula: the empirical formula of Magnesium Oxide 1. Purpose: Determine the empirical formula of magnesium oxide from the percent composition (this can found using the Analytical Method and the Synthesis Method).

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DETERMINATION OF A CHEMICAL FORMULA LAB ADV COMP 1 From Advanced Chemistry with Vernier, Vernier Software & Technology, INTRODUCTION John Dalton was an Englishman, a teacher, and an exceptional theoretical chemist. He developed and wrote the modern atomic theory at the turn of the 19th century . Introduction: In order to determine the chemical formula of a compound of the molar ration in the compound must be determined first by finding the mass. In this experiment the compound that was used was copper chloride hydrate%(6).