CH 151 Lab 3 -Saddam Hossain
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School
CUNY Queensborough Community College**We aren't endorsed by this school
Course
CH 151
Subject
Chemistry
Date
Dec 18, 2024
Pages
7
Uploaded by AmbassadorAtomLobster14
Name: Saddam Hossain General Chemistry 1Partners Name: Prof: Dr. Sujun Wei Lab Report 1. Fahmida Hoque 2. Daiana yosopov Title: Molar Mass of a Copper Compound Objectives:To determine the molar mass of an unknown copper compound through thermal decomposition. The molar mass will be calculated by measuring the mass of the compound before and after decomposition and comparing the results to theoretical values. Introduction: In this experiment, a sample of an unknown copper compound undergoes thermal decomposition to produce elemental copper. The mass of copper remaining after heating is used to calculate the molar mass of the original copper compound. The relationship between the moles of copper and the mass of the original compound allows for determination of its molar mass. Thermal decomposition involves heating a compound to break it down into simpler substances. For copper compounds, this often results in copper metal being isolated. Using the law of conservation of mass, the amount of copper metal produced can be correlated to the total amount of compound to calculate the molar mass. The molar mass of a substance is calculated by dividing the mass of the substance by the number of moles. In this experiment, the molar mass of copper (63.55 g/mol) is used as a reference. The relevant chemical reaction for copper decomposition can be generalized as: Where X represents the other elements in the compound.
Material:100 mL beaker Unknown copper compound (#21) Analytical balance (±0.0001 g precision) Bunsen burner (or hot plate) Crucible tongs Distilled water Heat-resistant gloves Safety goggles Chemical Used:Copper compound (Unknown #21), CuX Copper, Cu, Molar mass=63.55 g/mol
Procedure 1.A clean and dry 100 mL beaker was weighed and recorded as 51.1739 g. 2.A small amount of unknown copper compound (#21) was added to the beaker. The mass of the beaker plus copper compound was recorded as 51.39 g. 3.The mass of the copper compound was calculated by subtracting the mass of the empty beaker, giving a value of 0.22 g for the copper compound. 4.The beaker containing the copper compound was heated using a Bunsen burner until decomposition occurred. During heating, slight color changes were observed, indicating the decomposition of the compound. 5.After the first heating, the beaker and remaining copper were allowed to cool, and the mass was recorded as 51.29 g. A second round of heating was conducted to ensure complete decomposition, and the mass was recorded as 51.28 g. 6.The mass of the copper metal was determined by subtracting the mass of the beaker after heating from the original beaker’s mass, resulting in 0.11 g of copper metal.7.The moles of copper were calculated using the known molar mass of copper (63.55 g/mol), resulting in 0.0017 molof copper. Observations:The color of the compound changed during heating, indicating decomposition. The mass of the beaker decreased slightly after heating, showing that some volatile materials were released from the copper compound. A shiny copper residue remained in the beaker after decomposition.
Data and Calculation:
Sources of error: being isolated, leading to an overestimation of the molar mass. release of some volatile components before complete decomposition) could affect the final mass readings. affecting the accuracy of mass measurements.
Conclusion: The experiment successfully achieved its objective of determining the molar mass of an unknown copper compound. The mass of copper isolated after decomposition allowed for the calculation of the molar mass, which was found to be 127.12 g/mol.The mass percent of copper in the compound was determined to be 50.00% which aligns with the expected results for copper-based compounds. Further comparison to the theoretical molar mass of the copper compound (if known) would allow for the calculation of percent error, providing insight into the experiment's accuracy. The principles of stoichiometry and mass conservation were applied to correlate the mass of copper produced with the original copper compound. Any observed deviations could be due to incomplete decomposition or experimental limitations, such as potential loss of material during heating.