...Stoichiometry ________________________________________ Stoichiometry is simply the math behind chemistry. Given enough information, one can use stoichiometry to calculate masses, moles, and percents within a chemical equation. ________________________________________ ________________________________________ What is a Chemical Equation? In chemistry, we use symbols to represent the various chemicals. Success in chemistry depends upon developing a strong familiarity with these basic symbols. For example, the symbol "C"represents an atom of carbon, and "H" represents an atom of hydrogen. To represent a molecule of table salt, sodium chloride, we would use the notation "NaCl", where "Na" represents sodium and "Cl" represents chlorine. We call chlorine "chloride" in this case because of its connection to sodium. You should have reviewed naming schemes, or nomenclature, in earlier readings. A chemical equation is an expression of a chemical process. For example: AgNO3(aq) + NaCl(aq) ---> AgCl(s) + NaNO3(aq) In this equation, AgNO3 is mixed with NaCl. The equation shows that the reactants (AgNO3 and NaCl) react through some process (--->) to form the products (AgCl and NaNO3). Since they undergo a chemical process, they are changed fundamentally. Often chemical equations are written showing the state that each substance is in. The (s) sign means that the compound is a solid. The (l) sign means the substance is a liquid. The (aq) sign stands for aqueous in water and means...
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...Chem 200 (8/28) * Chapter 1 and 2 homework ( paper) turn in next week (wed) pg 217 in lab manual * Quiz 1 in discussion sections next week * Connect homework is live -chapter 1 and 2 due sept 6 * Know common elements and ions-lab manual/syllabus pages 14-16 * Read Chapters for exams Notes Errors in measurements * Radom error: all measurements have some level of random error they can be either positive( measure more than you actually do ) or negative errors( measure less then you usually do ) * Systematic error: always the same direction (either positive or negative) Precision and Accuracy * Precision : how reproducible each measurement is , how close each measurement is to the other measurements * Accuracy : how close the measured values are to the true value. Temperature Conversions (on the exam) Chemical Language * Elements (Na,Cl)- letters of the language * Chemical Formulas (NaCl)- words of the language Water Vs. Hydrogen Peroxide (on the exam) * The use of Hydrogen peroxide: nuclear, bomb, bleach hair,etc * Molecular formula : water: H2O, Hydrogen Peroxide : H2o2 * Empirical Formula: water HO, Hydrogen peroxide: HO * Structural Formula : water HOH, hydrogen peroxide: HOOH quetion: how many atoms of carbon, hydrogen, and oxygen are present in a single molucule of citric acid C3H5O(CO2H)3 Carbon: 6 Hydrogen :8 Oxygen: 7 Chemical Bonding * Bonds form between atoms when they share electrons * Different...
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...%. The percent yield is only 83.16 % because some product was lost during vacuum filtration. This loss could have been prevented by using colder water to transfer the crystals. The retrieve all of the crystals out of the flask, cool water was used. This caused some of the crystal dissolved and pass through the filter. The use of colder waster would prevent the crystals from dissolving. However, the amount that was lost was minimal, and the identification of the product was still confirmed by melting point, IR, and NMR. The melting point for the product was found to be 164-166 ˚C. This range coincides with the...
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...Pepsi and waste water. Many parameters were taken in consideration to test the water including physical conditions such as smell, color, turbidity and chemical conditions such as pH, DO, E.coli, TDS and NaCl present in the samples. Finally, a comparative analysis was done to assess the water quality of each samples based on the results from the experiment done. INTRODUCTION Importance of Water: With two thirds of the earth's surface covered by water and the human body consisting of 75 percent of it, it is evidently clear that water is one of the prime elements responsible for life on earth. Water circulates through the land just as it does through the human body, transporting, dissolving, replenishing nutrients and organic matter, while carrying away waste material. Further in the body, it regulates the activities of fluids, tissues, cells, lymph, blood and glandular...
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...Classification Tests for Hydroxyl- and Carbonyl-containing Compounds Miguel, K.D., Moron, R.S.S., Pazon, A.D., Ramirez, C.V., Raquepo, T.M.R., Razon, D.N.A.Jr. 2B-PH, Group No. 6, Department of Pharmacy, Faculty of Pharmacy, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines Abstract In organic chemistry it is very common to see molecules comprised mainly of a carbon backbone with functional groups attached to the chain. The functional group gives the molecule its properties, regardless of what molecule contains it.[1] Examples of functional groups are that of hydroxyl (-OH) which is usually seen in alcohols, and carbonyl (C=0) which is seen in aldehydes and ketones. In this experiment, several tests were conducted to distinguish and differentiate various sample compounds such as ethanol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, benzyl alcohol, n-butyraldehyde, benzaldehyde, acetone, acetophenone, isopropyl alcohol, and acetaldehyde. The tests are the following: solubility test of alcohols in water, which gave a soluble result in ethanol, sec-butyl alcohol and tert-butyl alcohol. Next is the Lucas test, which is used to differentiate 1°, 2° & 3° alcohols. In Lucas test, tert-butyl alcohol gave an immediate turbid result; the rate of reaction was noted. Chromic Acid test (Jones Oxidation) which gave a positive result by producing a blue-green solution with the sample n-butyl alcohol, acetaldehyde, benzaldehyde, and isopropyl alcohol. 2...
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...Yeast Culture Lab I. Introduction 1. Yeasts are eukaryotic, unicellular fungi that inhabit liquid or moist habitats. They are heterotrophs and rely on complex organic substances for nutrition. Yeasts require oxygen for aerobic cellular respiration but some are also anaerobic with alternative aerobic methods for producing energy. They do not require light to grow and their temperature range varies which means they can survive in a multitude of different environments. Very common, they can be found anywhere, from occurring on the skins of fruits to residing in the intestinal tracts of animals as parasites. The most common method of reproduction for yeasts is asexual reproduction through budding. In this process, the parent cell’s nucleus splits and forms a daughter nucleus. The daughter cell grows on the parent cell until it is large enough to separate. Through cytokinesis, this ‘bud’ then forms a new cell. Less common is the method of sexual reproduction in which spores are formed. In this lab, I will be culturing four yeast samples under different conditions. The goal is to study the effects of limited reproduction, additional resources (nutrition) and predation on the yeast population. Yeasts play a very important role not only by serving as nutrient recyclers in nature, but by also being important for the food industry because they can convert carbohydrates to carbon dioxide and alcohols through fermentation. They are also used in cell biology research and produce ethanol...
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...Microbiology Exam 3 Amber E. Baity Excelsior College 1.Blood isolated from an emergency room patient contains antibodies against the measles virus. Please explain whether or not the patient should be quarantined immediately because they are infected with the measles virus and why? What are the other plausible explanations for anti-measles antibodies in the patient’s blood? Though this could appear a critical situation, this patient does not need to be quarantined, as we do not know if the antibodies present in his body are from a current infection or due to a vaccination. Measles and mumps antibodies are virus-specific proteins produced by the immune system in response to an infection by the measles or mumps virus, or in response to vaccination. There are two types of antibodies produced, IgM and IgG. The first type to appear in the blood after exposure or vaccination is IgM antibodies. Levels of IgM antibodies increase for several days to a maximum concentration and then begin to taper off over the next few weeks. IgG antibodies take a bit longer to appear, but once they do, they stay in the bloodstream for life, providing protection against re-infection. When measles or mumps IgG antibody is present in a person who has been vaccinated and/or is not currently ill, then that person is protected against infection (immune). If a person does not have measles or mumps IgG antibodies, then they are not considered immune to the viruses. This may be because they have not been...
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...ENV 122 Lab 04: Habitable Planet Carbon Cycle This lab is developed from the Habitable Planet Interactive Carbon Lab found at https://www.learner.org/courses/envsci/interactives/carbon/ Overview This lab uses a robust model of the carbon cycle to give you an intuitive sense for how carbon circulates through the atmosphere, biosphere, oceans, and crust. This model is similar to ones presented by the Intergovernmental Panel on Climate Change (IPCC). It allows you to experiment with how human input to the cycle might change global outcomes to the year 2100 and beyond. One particularly relevant human impact is the increase in atmospheric CO2 levels. Between the years 1850 and 2015, atmospheric concentrations have risen from 290 parts per million (ppm) to over 400 ppm - a level higher than any known on Earth in more than 30 million years (see Unit 12 to find out how scientists measure ancient atmospheric carbon levels). Using the simulator, you will experiment with the human factors that contribute to this rise and explore how different inputs to the carbon cycle might affect the concentrations of the greenhouse gas CO2. Procedure Read through the material and follow the directions provided on the Habitable Planet website (unless otherwise instructed). Fill in the tables below with your data and answer the questions. Note: DO NOT download the data tables provided on the HP website. This file contains everything you will need. Save your file as: LASTNAME-Lab04-HPCarbonCycle...
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...neither were harmed (ladybugs ate the aphids who were eating the plants, now the plants are no longer pest-infected). In our aquatic environment, guppies interact with the anacharis plants by using them as a food source and the babies use them as a shelter for hiding. Carbon is a major component in life and is the major component to all organic compounds, which includes carbohydrates, lipids, proteins, and nucleic acids. Carbon dioxide is continuously exchanged between the atmosphere and oceans through chemical and physical processes. Both of the identified autotrophs and heterotrophs in our Ecocolumns contribute to carbon cycle. The pinto bean plant or anacharis (autotrophs) use carbon dioxide produced by heterotrophs to produce glucose and oxygen, which are then used by the heterotrophs. Another way that the identified autotrophs and heterotrophs contribute to the carbon cycle is when the organisms die, decomposers break down their bodies and release carbon into the environment. 2. Biotic and abiotic factors also interact for proper ecosystem function. Describe how the biotic and abiotic factors of your terrestrial environment interacted to contribute to nitrogen cycling. Be sure to cite specific observations from your Ecocolumn that relate to the nitrogen cycle. In our Ecocolumn, both the abiotic and biotic factors of the terrestrial environment contributed to the nitrogen cycle. All organisms require nitrogen to make amino acids, which are used to build nucleic acids, which...
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...Jacinta Houng Comparing the Solubility of Chemicals in Water “Water is known as the “universal solvent” because so many different substances dissolve in it and we rely on this for many of our daily needs.” Introduction: Water is known as the ‘universal solvent’ as it is capable of dissolving a variety of different substances and dissolves more substances than any other liquid. However the ability to be soluble depends on a substances polarity and bonding. This then contributes to the various ways that different types of chemicals interact in water. Solubility is crucial to every living thing on earth as water can carry along valuable chemicals, minerals, and nutrients necessary for survival. In fact Water covers 70% of the Earths surface and composes 55-70% of the human body. Water is an excellent solvent due to its chemical composition and physical attributes. According to USGS (http://water.usgs.gov/edu/qa-solvent.html ) Water molecules have a polar arrangement of the oxygen and hydrogen atoms—one side (hydrogen) has a positive electrical charge and the other side (oxygen) has a negative charge. A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. This causes the molecule to have a slight electrical dipole moment where one end is slightly positive and the other is slightly negative. "Like dissolves like" is an expression used by chemists to help them remember how solvents work. The expression refers to...
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...Dissolved Oxygen Measurement Page Section 1: Dissolved Oxygen (DO) Introduction 2 Section 2: Glossary 2 Section 3: Approved Methods 3 Section 4: Safety and Hygiene 3-4 Section 5: Sampling 4-5 Section 6: Effects of Temperature on DO 5 Section 7: Interpretations 5 Quiz 4.1 6 Section 8: Modified Winkler Method 6-9 Quiz 4.2 9 Section 9: The Electrometric Meter Method 9-11 Quiz 4.3 12 Section 10: QA/QC 12 Answers to Quizzes 13-14 Appendix A: References Appendix B: Dissolved Oxygen Reagents Appendix C: Sample Bench Sheets Chapter 4 DISSOLVED OXYGEN MEASUREMENT Section 1 : DISSOLVED OXYGEN (DO) INTRODUCTION The DO determination measures the amount of dissolved (or free) oxygen present in water or wastewater. Aerobic bacteria and aquatic life such as fish must have DO to survive. Aerobic wastewater treatment processes use aerobic and facultative bacteria to break down the organic compounds found in wastewater into more stable products that will not harm the receiving waters. Wastewater treatment facilities such as lagoons or ponds, trickling filters and activated sludge plants depend on these aerobic bacteria to treat sewage. The same type of aerobic wastewater treatment process occurs naturally in streams and ponds if organic matter is present, turning these bodies of water into “aerobic wastewater treatment plants.” If sufficient oxygen is not naturally supplied through wind and turbulence to replace the depleted oxygen, the body...
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...Dissolved Oxygen Measurement Page Section 1: Dissolved Oxygen (DO) Introduction 2 Section 2: Glossary 2 Section 3: Approved Methods 3 Section 4: Safety and Hygiene 3-4 Section 5: Sampling 4-5 Section 6: Effects of Temperature on DO 5 Section 7: Interpretations 5 Quiz 4.1 6 Section 8: Modified Winkler Method 6-9 Quiz 4.2 9 Section 9: The Electrometric Meter Method 9-11 Quiz 4.3 12 Section 10: QA/QC 12 Answers to Quizzes 13-14 Appendix A: References Appendix B: Dissolved Oxygen Reagents Appendix C: Sample Bench Sheets Chapter 4 DISSOLVED OXYGEN MEASUREMENT Section 1 : DISSOLVED OXYGEN (DO) INTRODUCTION The DO determination measures the amount of dissolved (or free) oxygen present in water or wastewater. Aerobic bacteria and aquatic life such as fish must have DO to survive. Aerobic wastewater treatment processes use aerobic and facultative bacteria to break down the organic compounds found in wastewater into more stable products that will not harm the receiving waters. Wastewater treatment facilities such as lagoons or ponds, trickling filters and activated sludge plants depend on these aerobic bacteria to treat sewage. The same type of aerobic wastewater treatment process occurs naturally in streams and ponds if organic matter is present, turning these bodies of water into “aerobic wastewater treatment plants.” If sufficient oxygen is not naturally supplied through wind and turbulence to replace the depleted oxygen, the body...
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...When plankton dies off, their calcium carbonate shells sink to the ocean floor, which is crucial for removing carbon dioxide from the atmosphere and absorbing it. There have been several studies conducted to see zooplankton’s adaptability to more acidic water; however, “experiments in the lab and at carbon dioxide seeps (where pH is naturally low) have found that foraminifera do not handle higher acidity very well, as their shells dissolve rapidly. One study even predicts that foraminifera from tropical areas will be extinct by the end of the century” (“Ocean Acidification”). It is important to remember phytoplankton’s key role in the ocean’s ecosystems by reinforcing the fact that, “Phytoplankton are important source of food for fish and invertebrates. They assist in maintaining pH and dissolved oxygen levels in marine ecosystems by removing carbon dioxide (CO2), and by adding oxygen (O2) as a result of their photosynthetic activity” (“Primary Production and Seawater Nutrient Analysis”). If the foundation of the food chain is wiped out, it will not take long for the rest of the food chain to end up in complete disarray and for carbon dioxide levels to increase. In summary, the overall health of the ocean lies in these little critter’s grasp and in our...
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...Cell Membrane Transport Harjot Dhesi Zoology 2011-13 Amon Gekombe 17 February 2014 Introduction The human body must maintain a balance within itself in order to abstain from disturbances caused by the external environment, for example a sudden increase in the outside temperature, or even the internal environment of the body, such as a dramatic drop in blood pressure. The body maintains this equilibrium through various methods and regulators, beginning in the cellular level. The human cell has a selectively permeable plasma membrane, allowing only certain substances to easily pass through to reach the inside or outside of the cell. Small, uncharged, and nonpolar molecules pass with the most ease through the plasma membrane (Tortora and Derrickson 2012). The constant moving in and out of substances is crucial in sustaining the life of the cell. Tortora and Derrickson explain in their book Principles of Anatomy and Physiology that, “Certain substances must move into the cell to support metabolic reactions. Other substances that have been produced by the cell for export or as cellular waste products must move out of the cell” (Tortora Derrickson 2012). Because of the selectively permeable nature of its plasma membrane, the cell can retain chemicals that have a difference in concentration on the inside than on outside of the cell. This is called the concentration gradient. A substance can either move against its concentration gradient by an active process, which requires...
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...PHYSICAL PROPERTIES OF THE PERIOD 3 OXIDES These pages explain the relationship between the physical properties of the oxides of Period 3 elements (sodium to chlorine) and their structures. Argon is obviously omitted because it doesn't form an oxide. A quick summary of the trends The oxides The oxides we'll be looking at are: |Na2O |MgO |Al2O3 |SiO2 |P4O10 |SO3 |Cl2O7 | | | | | |P4O6 |SO2 |Cl2O | Those oxides in the top row are known as the highest oxides of the various elements. These are the oxides where the Period 3 elements are in their highest oxidation states. In these oxides, all the outer electrons in the Period 3 element are being involved in the bonding - from just the one with sodium, to all seven of chlorine's outer electrons. The structures The trend in structure is from the metallic oxides containing giant structures of ions on the left of the period via a giant covalent oxide (silicon dioxide) in the middle to molecular oxides on the right. Melting and boiling points The giant structures (the metal oxides and silicon dioxide) will have high melting and boiling points because a lot of energy is needed to break the strong bonds (ionic or covalent) operating in three dimensions. The oxides of phosphorus, sulphur and chlorine consist of individual molecules - some small and simple; others polymeric. The attractive forces between these molecules...
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