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Chem 106 Lab Report 1 Assignment...

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Labs 1 and 2 Lab 1: “What is Around Us? ‘Chemistry is Life’” Experimental/ Observations: Molecular Compounds: 1. SbCl3- Antimony Trichloride 2. P2S3- Diphosphorus Trisulfide 3. AsBr3 Arsenic tribromide 4. CCl4- Carbon tetrachloride 5. AsF5- Arsenic Pentafluoride 6. TeBr2- Tellurium Dibromide 7. Si3As4- Trisilicon tetraarsenic 8. ClO3- Chlorate 9. BrCl- Bromine Monochloride 10. BCl3- Boron Trichloride 11. Cl(OH)- Hypochlorous acid 12. ClO- Hypochlorite 13. IF- Iodine monofluoride 14. PO4- Phosphate 15. PCl3- Phosphorus trichloride 16. Br3P- Phosphorus tribromide 17. AsCl- Arsenic Chloride 18. As2O3- Arsenic Trioxide 19. SCl- Sulfur Chloride 20. Pl3- Phosphorus Iodide 21. BrN- Bromide Nitride 22. AsN- Arsenic Nitride 23. SeBr- Selenium Bromide 24. AsI3- Arsenic Triiodide 25. PN- Phosphorus Mononitride

Ionic Compounds: 1. Ca3(PO4)2- Calcium Phosphate 2. CaCO3- Calcium Carbonate 3. RbNO2- Rubidium Nitrite 4. RbNO3- Rubidium Nitrate 5. CoO- Cobalt (II) Oxide 6. SnSe- Tin (II) Selenide 7. MgBr2- Magnesium Bromide 8. LiCl- Lithium Chloride 9. LiBr- Lithium Bromide 10. KCl- Potassium Chloride 11. KBr- Potassium Bromide 12. K3As- Potassium Arsenide 13. CoCl2 - Cobalt (II) Chloride 14. CaCl2 - Calcium Chloride 15. Co2O3 - Cobalt (III) Oxide 16. Ca(NO3)2 - Calcium Nitrate 17. Rb2S - Rubidium Sulfide 18. SnO2 - Tin (IV) Oxide 19. RbBr - Rubidium Bromide 20. SnF2 - Tin (II) Fluoride 21. RbNO2 - Rubidium Nitrite 22. Sn(OH2) - Tin (II) Hydroxide 23. AlBr3 - Aluminum Bromide 24. Sn3(AsO4)2 - Tin (II) Arsenate 25. PbBr4 - Lead (IV) Bromide

Focus Questions: 1. There are two types of compounds that I know of. One of them is called ionic compounds which are compounds usually composed of at least one metal and one nonmetal or two metal elements. The other one, covalent compounds, are made up of at least two nonmetal elements. 2. The rules for naming both ionic and molecular compounds are generally the same. For both ionic and molecular compounds, the name of the second compound gets changed so it ends in ‘ide’(Ex: hydrogen= hydride, fluorine= fluoride). For ionic compounds, with transition metals, a roman numeral needs to be inserted after the name of the metal to indicate the transition metal’s charge (ex: FeCl= Iron (I) Chloride). In molecular

compounds, since there are no ionic charges to balance out, it is important to use prefixes (ex: N2O5= dinitrogen pentoxide). 3. The order in which elements are combined when writing chemical formulas do matter. For ionic compounds, the order of the elements is that the positive ion is listed first and the negative ion is listed second. Although the general rule is to write the elements out in alphabetical order, most ionic compounds are an exception to this rule. 4. There are three laws that govern the formation of compounds. They are the law of conservation of mass, the law of multiple proportions and the law of definite proportions. Post Lab Assessment Questions: 1. For the following pairs of ions, write the formula of the compound that you would expect them to form: a. Magnesium and Cyanide: Mg(CN)2 b. Chromium (III) and Oxygen: Cr2O3 c. Cobalt (III) and Sulfite: CO2(SO4)3 2. Platinum is a transition metal and forms two different ions: Pt2+ and Pt 4+. Write the formulas for the compounds for each platinum ion with” a. Fluorine ions: F2Pt b. Hydroxide ions: H4O2Pt c. Chromate ions: Pt(CrO4)2 3. Name the following compounds: a. SO3- sulfur trioxide b. GaCl3- gallium trichloride c. Li3PO4- lithium phosphate d. TiO2- Titanium dioxide 4. Write the formulas for the following compounds: a. Sulfur pentachloride- SCl5 b. Nitrogen Dioxide- NO2 c. Zinc (II) Nitrate- Zn(NO3)2 d. Barium Sulfide- BaS

Lab 2: “Is Volume Conserved? The sneaky ethanol molecules” Introduction: To put it simply, volume can be defined as “the space taken up by an object”. Although it is known that when it comes to mass, matter can be neither created nor destroyed. For volume, however, most chemical and physical properties are not conserved during a reaction. Even more so when a reaction includes gases as reactants or products. For the purpose of our experiment, we explored whether or not volume is conserved during a chemical reaction involving ethanol and water. We did this by first calculating the densities of ethanol and water separately before mixing them and making solutions at different concentrations of both alcohol and water. We then calculated the experimental average densities of each solution and compared it to the expected densities to get a sense of whether or not volume was conserved during the experiment. Experimental/Observations: Data Table 1:

Data Table 2:

Graph:

Focus Question: When you mix alcohol and water is the volume conserved? Why or why not? Explain using your data and think about molecular packing mentioned in the introduction above. Volume is not conserved when water is mixed with alcohol. In fact, it is reduced due to molecular packing. Open spaces in the mixture are greatly reduced due to the fact that the two different molecules pack closer together than they would if they were pure solutions which reduces the overall volume. Discussion/Conclusion: After conducting this experiment, I found that in a reaction involving ethanol and water, the volume does reduce. As can be seen in data table two, the expected density is significantly lower than the experimental density. This is due to the fact that molecules in ethanol pack closely together and find and fill spaces in between water molecules rather than just sitting on top of each other. The data our group collected is higher than what was expected and this could be due to some possible mistakes we could’ve made. For example, we may have incorrectly measured the amount of liquid in the different graduated cylinders or we could have incorrectly calculated the mass of the graduated cylinders. Although our data isn’t the same as what was expected, it is consistently decreasing as we go down the solutions column similarly to the expected column of table 3.

Post-Lab Questions: 1. Based on what I did and learned today, I would predict for the mass to stay the same since mass can be neither created or destroyed but I would expect for the volume to decrease. 2. When I mix two gases, I can predict for the volume to increase as gases expand to fill the volume of their containers. 3. In this reaction, there won't be any volume conservation but the mass will be equal to the sum of the hydrogen gas and the oxygen gas reacting. 4. I predict the density of a 43% solution of ethanol in water to be about ~.908 g/mL. 5. The experimental density is higher than the expected density which goes to show that the expected densities support the fact that volume is not preserved in a reaction with alcohol and water.

References: Endmemo. (n.d.). Retrieved February 16, 2021, from http://www.endmemo.com/chem/compound/ptcro4_2.php Forming chemical compounds. (n.d.). Retrieved February 16, 2021, from http://nuclearpowertraining.tpub.com/h1015v1/css/Forming-Chemical-Compounds-54.htm#:~:te xt=There%20are%20three%20basic%20laws,compounds%20behave%20as%20they%20do Lohninger, H. (n.d.). Volume relationships in chemical reactions. Retrieved February 16, 2021, from http://www.vias.org/genchem/atommasses_12431_03.html#:~:text=Although%20mass%20is%2 0conserved%2C%20most,explosively%20to%20form%20water%20vapor. Order of elements in a chemical formula. (n.d.). Retrieved February 16, 2021, from https://www.school-for-champions.com/chemistry/formula_order.htm#.YCrin89KhJV Smeureanu, G. & Geggier, S. (2020). General Chemistry Laboratory. New York, NY Wolfe, E. (2017, April 05). 4 steps to Naming compounds in CHEMISTRY NOMENCLATURE. Retrieved February 16, 2021, from https://medium.com/countdown-education/4-steps-to-naming-compounds-in-chemistry-nomencl ature-7525ed57bd13...