6—Evaluation of the Gas Law Constant
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Experiment 5: Molar Volume of a Gas (Mg + Hcl)
1 CHEM 30A EXPERIMENT 5: MOLAR VOLUME OF A GAS (MG + HCL) Learning Outcomes Upon completion of this lab, the student will be able to: 1) Demonstrate a single replacement reaction. 2) Calculate the molar volume of a gas at STP using experimental data. 3) Calculate the molar mass of a metal using experimental data. Introduction Metals that are above hydrogen in the activity series will displace hydrogen from an acid and produce hydrogen gas. Magnesium is an example of a metal that is more active than hydrogen in the activity series. The reaction between magnesium metal and aqueous hydrochloric acid is an example of a single replacement reaction (a type of redox reaction). The chemical equation for this reaction is shown below: Mg(s) + 2HCl(aq) è MgCl2(aq) + H2(g) Equation 1 When the reaction between the metal and the acid is conducted in a eudiometer, the volume of the hydrogen gas produced can be easily determined. In the experiment described below magnesium metal will be reacted with an excess of hydrochloric acid and the volume of hydrogen gas produced at the experimental conditions will be determined. According to Avogadro’s law, the volume of one mole of any gas at Standard Temperature and Pressure (STP = 273 K and 1 atm) is 22.4 L. Two important Gas Laws are required in order to convert the experimentally determined volume of hydrogen gas to that at STP. 1. Dalton’s law of partial pressures. 2. Combined gas law. Dalton’s Law of Partial Pressures According to Dalton’s law of partial pressures in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases. -
Use of Laboratory Equipement
USE OF LABORATORY EQUIPEMENT C. Laboratory Thermometers Most thermometers are based upon the principle that liquids expand when heated. Most common thermometers use mercury or colored alcohol as the liquid. These thermometers are constructed as that a uniform-diameter capillary tube surmounts a liquid reservoir. To calibrate a thermometer, one defines two reference points, normally the freezing point of water (0°C, 32°F) and the boiling point of water (100°C, 212°F) at 1 tam of pressure (1 tam = 760 mm Hg). Once these points are marked on the capillary, its length is then subdivided into uniform divisions called degrees. There are 100° between these two points on the Celsius (°C, or centigrade) scale and 180° between those two points on the Fahrenheit (°F) scale. °F = 1.8 °C + 32 The Thermometer and Its Calibration This section describes the proper technique for checking the accuracy of your thermometer. These measurements will show how measured temperatures (read from thermometer) compare with true temperatures (the boiling and freezing points of water). The freezing point of water is 0°C; the boiling point depends upon atmospheric pressure but at sea level it is 100°C. Option 1: Place approximately 50 mL of ice in a 250-mL beaker and cover the ice with distilled water. Allow about 15 min for the mixture to come to equilibrium and then measure and record the temperature of the mixture. Theoretically, this temperature is 0°C. Option 2: Set up a 250-mL beaker on a wire gauze and iron ring. Fill the beaker about half full with distilled water. -
Solutes and Solution
Solutes and Solution The first rule of solubility is “likes dissolve likes” Polar or ionic substances are soluble in polar solvents Non-polar substances are soluble in non- polar solvents Solutes and Solution There must be a reason why a substance is soluble in a solvent: either the solution process lowers the overall enthalpy of the system (Hrxn < 0) Or the solution process increases the overall entropy of the system (Srxn > 0) Entropy is a measure of the amount of disorder in a system—entropy must increase for any spontaneous change 1 Solutes and Solution The forces that drive the dissolution of a solute usually involve both enthalpy and entropy terms Hsoln < 0 for most species The creation of a solution takes a more ordered system (solid phase or pure liquid phase) and makes more disordered system (solute molecules are more randomly distributed throughout the solution) Saturation and Equilibrium If we have enough solute available, a solution can become saturated—the point when no more solute may be accepted into the solvent Saturation indicates an equilibrium between the pure solute and solvent and the solution solute + solvent solution KC 2 Saturation and Equilibrium solute + solvent solution KC The magnitude of KC indicates how soluble a solute is in that particular solvent If KC is large, the solute is very soluble If KC is small, the solute is only slightly soluble Saturation and Equilibrium Examples: + - NaCl(s) + H2O(l) Na (aq) + Cl (aq) KC = 37.3 A saturated solution of NaCl has a [Na+] = 6.11 M and [Cl-] = -
Ear and Forehead Thermometer
Ear and Forehead Thermometer INSTRUCTION MANUAL Item No. 91807 19.PJN174-14_GA-USA_HHD-Ohrthermometer_DSO364_28.07.14 Montag, 28. Juli 2014 14:37:38 USAD TABLE OF CONTENTS No. Topic Page 1.0 Definition of symbols 5 2.0 Application and functionality 6 2.1 Intended use 6 2.2 Field of application 7 3.0 Safety instructions 7 3.1 General safety instructions 7 3.3 Environment for which the DSO 364 device is not suited 9 3.4 Usage by children and adolescents 10 3.5 Information on the application of the device 10 4.0 Questions concerning body temperature 13 4.1 What is body temperature? 13 4.2 Advantages of measuring the body tempera- ture in the ear 14 4.3 Information on measuring the body tempera- ture in the ear 15 5.0 Scope of delivery / contents 16 6.0 Designation of device parts 17 7.0 LCD display 18 8.0 Basic functions 19 8.1 Commissioning of the device 19 8.2 Warning indicator if the body temperature is 21 too high 2 19.PJN174-14_GA-USA_HHD-Ohrthermometer_DSO364_28.07.14 Montag, 28. Juli 2014 14:37:38 TABLE OF CONTENTS USA No. Topic Page 8.3 Backlighting / torch function 21 8.4 Energy saving mode 22 8.5 Setting °Celsius / °Fahrenheit 22 9.0 Display / setting time and date 23 9.1 Display of time and date 23 9.2 Setting time and date 23 10.0 Memory mode 26 11.0 Measuring the temperature in the ear 28 12.0 Measuring the temperature on the forehead 30 13.0 Object temperature measurement 32 14.0 Disposal of the device 33 15.0 Battery change and information concerning batteries 33 16.0 Cleaning and care 36 17.0 “Cleaning” warning indicator 37 18.0 Calibration 38 19.0 Malfunctions 39 20.0 Technical specification 41 21.0 Warranty 44 3 19.PJN174-14_GA-USA_HHD-Ohrthermometer_DSO364_28.07.14 Montag, 28. -
22 Bull. Hist. Chem. 8 (1990)
22 Bull. Hist. Chem. 8 (1990) 15 nntn Cn r fr l 4 0 tllOt f th r h npntd nrpt ltd n th brr f th trl St f nnlvn n thr prt nd ntn ntl 1 At 1791 1 frn 7 p 17 AS nntn t h 3 At 179 brr Cpn f hldlph 8Gztt f th Untd Stt Wdnd 3 l 1793 h ntr nnnnt rprdd n W Ml "njn h Cht"Ch 1953 37-77 h pn pr dtd 1 l 179 nd nd b Gr Whntn th frt ptnt d n th Untd Stt S M ntr h rt US tnt" Ar rt Invnt hn 199 6(2 1- 19 ttrfld ttr fnjn h Arn hl- phl St l rntn 1951 pp 7 9 20h drl Gztt 1793 (20 Sptbr Qtd n Ml rfrn 1 1 W Ml rfrn 1 pp 7-75 William D. Williams is Professor of Chemistry at Harding r brt tr University, Searcy, Al? 72143. He collects and studies early American chemistry texts. Wyndham D. Miles. 24 Walker their British cultural heritage. To do this, they turned to the Avenue, Gaithersburg, MD 20877, is winner of the 1971 schools (3). This might explain why the Virginia assembly Dexter Award and is currently in the process of completing the took time in May, 1780 - during a period when their highest second volume of his biographical dictionary. "American priority was the threat of British invasion following the fall of Chemists and Chemical Engineers". Charleston - to charter the establishment of Transylvania Seminary, which would serve as a spearhead of learning in the wilderness (1). -
Determination of Calcium Metal in Calcium Cored Wire
Asian Journal of Chemistry; Vol. 25, No. 17 (2013), 9439-9441 http://dx.doi.org/10.14233/ajchem.2013.15017 Determination of Calcium Metal in Calcium Cored Wire 1,* 1 2 1 1 HUI DONG QIU , MEI HAN , BO ZHAO , GANG XU and WEI XIONG 1Department of Chemistry and Chemical Technology, Chong Qing University of Science and Technology, Chongqing 401331, P.R. China 2Shang Hai Entry-Exit Inspection and Quarantine Bureau, P.R. China *Corresponding author: Tel: +86 23 65023763; E-mail: [email protected] (Received: 24 December 2012; Accepted: 1 October 2013) AJC-14200 The calcium analysis method in cored wire products is mainly measuring the total calcium content, including calcium oxide and calcium carbonate. According to the chemical composition of calcium cored wire and the chemical property of the active calcium in it, the gas volumetric method has been established for the determination of calcium content in calcium cored wire and a set of analysis device is also designed. Sampling in the air directly, intercepting the inner filling material of samples, reacting with water for 10 min, using standard comparison method and then the accurate calcium content can be available. The recovery rate of the experimental method was 93-100 %, the standard deviation is less than 0.4 %. The method is suitable for the determination the calcium in the calcium cored wire and containing active calcium fractions. Key Words: Calcium cored wire, Active calcium, Gas volumetric method. INTRODUCTION various state of the calcium. However, because the sample is heterogeneous and the amount of the sample for instrumental 1-4 The calcium cored wire is used to purify the molten analysis is small, thus such sampling can not estimate charac- steel, modify the form of inclusions, improve the casting and teristics of the whole ones accurately, so there are flaws to use mechanical properties of the steel and also reduce the cost of the instrumental analysis to determine the calcium metal in steel. -
XXIX. on the Magnetic Susceptibilities of Hydrogen and Some Other Gases
Philosophical Magazine Series 6 ISSN: 1941-5982 (Print) 1941-5990 (Online) Journal homepage: http://www.tandfonline.com/loi/tphm17 XXIX. On the magnetic susceptibilities of hydrogen and some other gases Také Soné To cite this article: Také Soné (1920) XXIX. On the magnetic susceptibilities of hydrogen and some other gases , Philosophical Magazine Series 6, 39:231, 305-350, DOI: 10.1080/14786440308636042 To link to this article: http://dx.doi.org/10.1080/14786440308636042 Published online: 08 Apr 2009. Submit your article to this journal Article views: 6 View related articles Citing articles: 16 View citing articles Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=6phm20 Download by: [RMIT University Library] Date: 20 June 2016, At: 12:34 E 3o5 XXIX. On the MAgnetic Susceptibilities of llydrogen uud some otl~er Gases. /33/TAK~; S0~; *. INDEX TO SECTIONS. 1. INTRODUCTION. ~O. METI~OD OF 5LEASUREMENT. o. APPARATUS :FOR }IEASU14EIMF~NT. (a) Magnetic bMance. (b) Compressor and measuring tube. 4. PIt0CEDUI{E :FOR BIEASUREMENTS. (a) Adjustment of the measuring tube. (b) Determination of the mass. (c) Method of filling the measuring tube with gas. (d) Electromagnet. (e} Method of experiments. 5. Ain. 6. OXYGEN. ~. CARBON DIOXIDE. 8. NITROGEN. 9. ItYDI~0G~N. (a) Preparation of pure hydrogen gas. (b) Fillin~ the measuring tube with the gas. (e) YCesults el'magnetic measurement. (d} Purity of the hydrogen gas. 10. CONCLUDING REMARKS. wi. INTRODUCTION. N the electron theory of magnetism, it is assumed that I the magnetism is duo to electrons revolving about the positive nucleus in the atom; and hence the electronic structure of the atom has a very important bearing on its magnetic properties. -
A Study of Form and Content for a Laboratory Manual to Be Used by Students in General Chemistry Laboratory
Brigham Young University BYU ScholarsArchive Theses and Dissertations 1946-01-01 A study of form and content for a laboratory manual to be used by students in general chemistry laboratory Berne P. Broadbent Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd BYU ScholarsArchive Citation Broadbent, Berne P., "A study of form and content for a laboratory manual to be used by students in general chemistry laboratory" (1946). Theses and Dissertations. 8176. https://scholarsarchive.byu.edu/etd/8176 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. ?_(j;, . , i. ~ ~ (12 ' -8?5: 11% -· • A STUDY OF FOFM CONTENTFOR A LABORATORY -\ .AND MANUALTO BE USED BY STUDENTSIN GENERALCEEi/IISTRY LABORATORY' A THESIS SUBMITTEDTO \ THE DEPAR'.I3\t1Ell."'T OF CHEMISTRY OF ··! BRIGHAMYOUNG UNIVERSITY,. IN PARTIALFULFII.lllENT OF THEREQ,UIREMENTS·FOR THE DEGREE OF MASTEROF SCIENCE ... .,; . •·' .. ...• • .• . • "f ... ·.. .. ,. ·: :. !./:.•:-.:.lo>•.-,:... ... ... ..........• • • • p ,.. .,• • • ...• • . ~. ••,,. ................. :... ~•••,,.c • ..............• • • • • • .. f" ·~•-~-·"••• • • • ... • .., : :·.•··•:'"'•••:'"',. ·.-··.::· 147141 BY BERNEP. BROADBENT . " 1946 .,_ - ii \ ., This Thesis by Berne P.- Broadbent is accepted in 1ts P:esent form by the Departm·ent of Chem�stry as satisfying the Thesis requirement.for the degree of .J Master of Science • ,• . - .} .. iii PREF.ACE The constantly broadening field assigned to general chemistry demands that material be carefully selected and that ever increasing attention be given to preparing this material and presenting it_ to the student.- The following study was made to develop a laboratory manual that would increase the effectiveness of laboratory work. -
Ideal Gas Law PV = Nrt R = Universal Gas Constant R = 0.08206 L-Atm R = 8.314 J Mol-K Mol-K Example
Ideal gas law PV = nRT R = universal gas constant R = 0.08206 L-atm R = 8.314 J mol-K mol-K Example: In the reaction of oxygen with carbon to produce carbon dioxide, how many liters of oxygen at 747 mm Hg and 21.0 °C are needed to react with 24.022 g of carbon? CHEM 102 Winter 2011 Practice: In the reaction of oxygen and hydrogen to make water, how many liters of hydrogen at exactly 0 °C and 1 atm are needed to react with 10.0 g of oxygen? 2 CHEM 102 Winter 2011 Combined gas law V decreases with pressure (V α 1/P). V increases with temperature (V α T). V increases with particles (V α n). Combining these ideas: V α n x T P For a given amount of gas (constant number of particles, ninitial = nafter) that changes in volume, temperature, or pressure: Vinitial α ninitial x Tinitial Pinitial Vafter α nafter x Tafter Pafter ninitial = n after Vinitial x Pinitial = Vafter x Pafter Tinitial Tafter 3 CHEM 102 Winter 2011 Example: A sample of gas is pressurized to 1.80 atm and volume of 90.0 cm3. What volume would the gas have if it were pressurized to 4.00 atm without a change in temperature? 4 CHEM 102 Winter 2011 Example: A 2547-mL sample of gas is at 421 °C. What is the new gas temperature if the gas is cooled at constant pressure until it has a volume of 1616 mL? 5 CHEM 102 Winter 2011 Practice: A balloon is filled with helium. -
CHAPTER 15 the Laboratory
CHAPTER 15 The Laboratory These skills are usually tested on the SAT Subject Test in Chemistry. You should be able to . • Name, identify, and explain proper laboratory rules and procedures. • Identify and explain the proper use of laboratory equipment. • Use laboratory data and observations to make proper interpretations and conclusions. This chapter will review and strengthen these skills. Be sure to do the Practice Exercises at the end of the chapter. Laboratory setups vary from school to school depending on whether the lab is equipped with macro- or microscale equipment. Microlabs use specialized equipment that allows lab work to be done on a much smaller scale. The basic principles are the same as when using full-sized equipment, but microscale equipment lowers the cost of materials, results in less waste, and poses less danger. The examples in this book are of macroscale experiments. Along with learning to use microscale equipment, most labs require a student to learn how to use technological tools to assist in experiments. The most common are: Gravimetric balance with direct readings to thousandths of a gram instead of a triple-beam balance pH meters that give pH readings directly instead of using indicators Spectrophotometer, which measures the percentage of light transmitted at specific frequencies so that the molarity of a sample can be determined without doing a titration Computer-assisted labs that use probes to take readings, e.g., temperature and pressure, so that programs available for computers can print out a graph of the relationship of readings taken over time LABORATORY SAFETY RULES The Ten Commandments of Lab Safety The following is a summary of rules you should be well aware of in your own chemistry lab. -
Ideal Gasses Is Known As the Ideal Gas Law
ESCI 341 – Atmospheric Thermodynamics Lesson 4 –Ideal Gases References: An Introduction to Atmospheric Thermodynamics, Tsonis Introduction to Theoretical Meteorology, Hess Physical Chemistry (4th edition), Levine Thermodynamics and an Introduction to Thermostatistics, Callen IDEAL GASES An ideal gas is a gas with the following properties: There are no intermolecular forces, except during collisions. All collisions are elastic. The individual gas molecules have no volume (they behave like point masses). The equation of state for ideal gasses is known as the ideal gas law. The ideal gas law was discovered empirically, but can also be derived theoretically. The form we are most familiar with, pV nRT . Ideal Gas Law (1) R has a value of 8.3145 J-mol1-K1, and n is the number of moles (not molecules). A true ideal gas would be monatomic, meaning each molecule is comprised of a single atom. Real gasses in the atmosphere, such as O2 and N2, are diatomic, and some gasses such as CO2 and O3 are triatomic. Real atmospheric gasses have rotational and vibrational kinetic energy, in addition to translational kinetic energy. Even though the gasses that make up the atmosphere aren’t monatomic, they still closely obey the ideal gas law at the pressures and temperatures encountered in the atmosphere, so we can still use the ideal gas law. FORM OF IDEAL GAS LAW MOST USED BY METEOROLOGISTS In meteorology we use a modified form of the ideal gas law. We first divide (1) by volume to get n p RT . V we then multiply the RHS top and bottom by the molecular weight of the gas, M, to get Mn R p T . -
Infrared Forehead Thermometer (4DET-306) Quick Start Guide
Infrared Forehead Thermometer (4DET-306) Quick Start Guide To take a forehead temperature: 1” (2-3cm) 1 Press the power button , wait for 2 beeps. 2 Aim the thermometer at the center of the forehead about 1 inch (2-3 cm) from the skin and press the start button S T A R T . 2 START If the body temperature is below 100°F (38.7°C) you will hear one short beep and a 1 happy face will appear on the display. If the body temperature is above 100°F (38.7°C) you will hear one long beep followed by three short beeps and a sad face will appear on the display. Detailed instructions are included in the packaging Temperature Taking Hints and Tips • All body site temperatures are not the same. The • Temporal artery temperature changes faster than a temperature taken at different sites on the body will vary temperature taken rectally, orally or under the arm. A significantly. A forehead (temporal) temperature, for difference of 1°F (.6°C) is normal. Body temperature can example, is usually 0.5°F (0.3°C) to 1.0°F (0.6°C) lower change throughout the day. than an oral temperature. • Consistently low temperature readings may be caused by a • Make certain the thermometer is in FOREHEAD MODE. dirty instrument window. Use an alcohol wipe or a cotton • Non-contact infrared thermometers measure surface swab moistened with alcohol (70% isopropyl) to clean the temperature. Hold the device approximately 1 inch (2-3 instrument window and housing. Gently wipe and let air dry.