General Chemistry 1 Quarter 1 Module 5 Gases I (2020) PDF

Senior High School NOT General Chemistry 1 Quarter 1 - Module 5 Gases I Pmixture = P1 + P2 + P3 𝑃1 𝑃2 =...

Senior High School NOT General Chemistry 1 Quarter 1 - Module 5 Gases I Pmixture = P1 + P2 + P3 𝑃1 𝑃2 = 𝑇1 𝑇2 𝑃1 𝑉1 = 𝑃2 𝑉2 𝑉1 𝑉2 = 𝑇1 𝑇2 Department of Education Republic of the Philippines General Mathematics- Grade 12 Alternative Delivery Mode Quarter 1 - Module 5: Gases I First Edition, 2020 Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalty. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this book are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Published by the Department of Education – Division of Cagayan de Oro Schools Division Superintendent: Dr. Cherry Mae L. Limbaco, CESO V Development Team of the Module Author/s: Allyn Y. Aclo, SPST-I, Engr. Shoji-an D. Daradal, SPST-I Reviewers: Jean S. Macasero, Ph.D. Illustrator and Layout Artist: Engr. Shoji-an D. Daradal, SPST-I Management Team Chairperson: Dr. Arturo B. Bayocot, CESO III Regional Director Co-Chairpersons: Dr. Victor G. De Gracia Jr. CESO V Asst. Regional Director Cherry Mae L. Limbaco, PhD, CESO V Schools Division Superintendent Alicia E. Anghay, PhD, CESE Assistant Schools Division Superintendent Mala Epra B. Magnaong, Chief ES, CLMD Members Neil A. Improgo, EPS-LRMS Bienvenido U. Tagolimot, Jr., EPS-ADM Lorebina C. Carrasco, OIC-CID Chief Ray O. Maghuyop, EPS-Math Joel D. Potane, LRMS Manager Lanie O. Signo, Librarian II Gemma Pajayon, PDO II Printed in the Philippines by Department of Education – Division of Cagayan de Oro City Office Address: Fr. William F. Masterson Ave Upper Balulang Cagayan de Oro Telefax: (08822)855-0048 E-mail Address: [email protected] i  Senior Senior High High School School General Chemistry 1 Quarter 1 - Module 5 Gases I This instructional material was collaboratively developed and reviewed by educators from public schools. We encourage teachers and other education stakeholders to email their feedback, comments, and recommendations to the Department of Education at [email protected] We value your feedback and recommendations. Department of Education Republic of the Philippines ii  Table of Contents What This Module is About………………………………………………………………………..iv What I Need to Know………………………………………………………………………………iv How to Learn from this Module…………………………………………………………………....v Icons of this Module…………………………………………………………………………………v What I Know…………………………………………………………………………………………vi Lesson 1: Pressure and its Units……………………………………………….1 What’s New…………...…………………………………………………………...2 What Is It: Pressure……………………………………………………………….2 What’s More: Reflection on Pressure…………………………………………...2 What Is It: Units of Pressure……………………………………………………..2 What’s More: Conversion of Units………………………………………………4 What I Have Learned……………………………………………………………..5 What I Can Do……………………………………………………………………..6 Lesson 2: Gas Laws……………………………………………………………………..7 What’s In……………………………………………………………………………7 What I Need to Know……………………………………………………………...7 What’s New: Graph Analysis……………………………………………………..8 What Is It: Gas Laws……………………………………………………………...9 What’s More: Gas Laws Calculations…………………………………………..13 What I Have Learned: Picture Analysis………………………………………...15 What Is It: Gas Mixtures………………………………………………………….16 What’s More: Gas Mixtures Calculations……………………………………….17 What I Can Do……………………………………………………………………..19 Summary……………………………………………………………………………………………..20 Assessment: Post-Test………………………………………………………………………….....21 Key to Answers……………………………………………………………………………………...22 References…………………………………………………………………………………………..24 iii  Module 5 Gases I What This Module is About This module demonstrates your understanding of the mathematical relationship between the pressure, volume, and temperature of a gas. It also tackles the partial pressures of a gas and its quantitative relationships of the reactants and products in a gaseous reaction and behaviour and properties of gases at the molecular level This module has two (2) lessons:  Lesson 1: Pressure and its Units  Lesson 2: Gas Laws What I Need to Know After going through this module, you are expected to: 1. Define pressure and give the common units of pressure (STEM_GC11G-Ih-i-43) 2. Use the gas laws to determine pressure, volume, or temperature of a gas under certain conditions of change (STEM_GC11G-Ih-i-45) 3. Use the Ideal Gas Equation to calculate pressure, volume, temperature, or number of moles of gas (STEM_GC11G-Ih-i-46) 4. Use Dalton’s Law of Partial Pressure to relate mole fraction and partial pressure of gases in a mixture. (STEM_GC11DL-Ii-47) _ iv How to Learn from this Module To achieve the objectives cited above, you are to do the following: Take your time reading the lessons carefully. Follow the directions and/or instructions in the activities and exercises diligently. Answer all the given tests and exercises. Icons of this Module What I Need to This part contains learning objectives that Know are set for you to learn as you go along the module. What I know This is an assessment as to your level of knowledge to the subject matter at hand, meant specifically to gauge prior related knowledge What’s In This part connects previous lesson with that of the current one. What’s New An introduction of the new lesson through various activities, before it will be presented to you What is It These are discussions of the activities as a way to deepen your discovery and under- standing of the concept. What’s More These are follow-up activities that are in- tended for you to practice further in order to master the competencies. What I Have Activities designed to process what you Learned have learned from the lesson What I can do These are tasks that are designed to show- case your skills and knowledge gained, and applied into real-life concerns and situations. v  What I Know MULTIPLE CHOICE. Directions: Read and understand each item and choose the letter of the best answer. Write your answers on the space provide before the number. __1. Which of the following description refers to pressure? a. It is the force exerted by colliding molecules per unit area of container walls. b. It refers to the force exerted by the wall. c. The force resulted from the molecules or particles in static. d. The resulting force from the bodies at rest or in equilibrium. __2. Which of the following is not a unit of pressure? a. Atm b. Torr c. mmHg d. none of the above __3. Which of the following refers to standard atmospheric pressure? a. Atm b. Torr c. mmHg d. Pa __4. One (1) atm is equal to what value of mmHg? a. 706 mmHg b. 273 mmHg c. 760 mmHg d. 101.3 kPa __5. The volume of a given amount of gas is inversely proportional to its pressure at constant temperature is stated by what law? a. Avogadro’s Law b. Charles’s Law c. Gay-Lussac Law d. Boyles Law __6. When volume on a gas goes up what happens to its pressure? a. stays the same b. goes down c. rises d. rises, then falls __7. Which of the following refers to the statement of Charles’ Law? a. The relationship of volume and pressure of a gas is inversely proportional. b. The relationship of volume and pressure of a gas is directly proportional. c. The relationship of temperature and volume of a gas is directly proportional. d. The relationship of temperature and volume of a gas is inversely proportional. __8. When the volume goes down the what happens to its temperature? a. rises b. goes up c. goes down d. rises, then falls __9. Which of the following gas laws describes the relationship of volume and moles? a. Boyle’s Law c. Charles’s Law b. Avogadro’s Law d. Ideal Gas Laws __10. Which of the following is the ideal gas equation? a. PV=NRT c. PV=nRT b. Pv=nrt d. pv=nRT vi  Lesson Pressure and its Units 1 What I Need to Know Get a ball or an inflated balloon. Feel the ball. Is it too hard? Too soft? Or does it feel just right? a basketball player knows the right feel of the ball, they say the “pressure” is just right. In the same way a jeepney driver can tell right away if the tire’s pressure is just right, too high, or too low. Everyone knows the important of pressure, but not all have an idea what is pressure. So, what does pressure mean? Why does the air inside the tire or a basketball exert pressure? Aside from it what are other variables that constitutes to the properties of gas? In this lesson, you are to define pressure and give common units of pressure. (a) (b) Look at the picture (a) shown above. What do you think is the role of the pressure of the gas inside the balloon? For picture (b) Imagine the tire of a vehicle and the need to pump air into the tire up to a given pressure. a. What will happen if the pressure is much lower than what it should be? b. What will happen if the pressure is much greater than what it should be? 1  What’s New Matching Type Direction: Match column A with column B. Write the letter of the correct answer on the space provided before the number. Column A Column B _____1. This is the most easily measured a. Torr gas property defined as the force exerted upon by colliding b. Atmosphere molecules per unit area of a surface. _____2. It refers to the equivalent unit of c. Evangelista millimeter of mercury (mmHg) Torricelli _____3. This instrument is commonly used to measure the pressure of d. Pressure a gas. _____4. An Italian physicist who invented e. Pascal the barometer _____5. It refers to a unit commonly used f. Barometer to express gas pressure. What Is It The entire universe is made up of matter including humans, animals, plants, and even the non-living things. There are three phases or states of matter, namely; solid, liquid, and gas. Moreover, gas behaves differently from solids and liquids due to differences in their molecular behavior. The movement of the gas is in random motion due to the vast empty space in a certain system since the distance per particles are far greater than the other two states of matter. Under some conditions of a gas sample, it can be defined in terms of its variables; temperature, volume, moles, and pressure. In the gaseous phase, molecules or the particles collide randomly against other molecules and against its container or its system. This random collision resulted changes in momentum which give way to the one of the property of gases called pressure. Pressure as one of the variables defines as the amount of force exerted per unit area. It refers to the force exerted by colliding molecules per unit area of container walls. 2  What’s More Time to Ponder! Direction. Reflect and make an essay about “Pressure in Everyday Life”. You may use some facts, based in your daily experiences or relate it in the emotional aspects. You may use an extra sheet of paper for this activity. What Is It What makes pressure quantifiable? How does pressure measured and expressed? The following details are some of the units that can be used for pressure: a. Standard Atmosphere (atm)  It is commonly Mercury Barometer and widely used unit for pressure in chemistry. The 1 atm is equal to the pressure that supports a column of mercury which is exactly 760 mmHg. b. Torr (or mmHg)  mmHg means millimeter of Pressure Pressure mercury, where it represents the pressure exerted by a column of a mercury which exactly equals to atmosphere. The unit mmHg is called torr, named after the Italian scientist Evangelista Torricelli, who also invented Barometer, a device used to measure the atmospheric pressure. c. Pounds per square inch (psi) If we say that gas exerts a pressure of 20 psi, it means the pressure on the wall of the gas container is 20 pounds or the 3  force per square inch of the unit area. The atmospheric pressure at sea level is 14.7 psi. d. kilopascal(kPa)  A kilopascal is equal to 1000 pascals (Pa). It is the standard unit for pressure. Conversion Factor: 1 atm = 760 mmHg = 760 torr = 101.3 kPa = 14.7 psi 1 kPa = 1000Pa What’s More Conversion Direction: Convert the following pressure to its desired unit that is asked in the question. Show your solution and encircle the final answer. 1. 1 atm to torr 6. 35 kPa to Pa 2. 14.7 psi to kPa 7. 450 000 Pa to kPa 3. 760 mmHg to psi 8. 5 atm to kPa 4. 725 torr to atm 9. 3 kPa to psi 5. 35 psi to atm 10. 530 mmHg to atm 4  What I Have Learned Direction: Answer the following questions as directed. For the calculations, show your solution and encircle the final answer. 1. What is pressure? 2. What are the different units that can be used to measure and express pressure? Then explain each briefly. (a.) (b.) (c.) (d.) 3. The pressure of the air on a mountain is 0.978 atm. What will be the pressure in the units of torr? 4. The pressure inside the tires of a backhoe is 40 psi. What will be the pressure in the units of atm? 5. The pressure of a certain valley below sea level is 200 kPa, what will be the height of the mercury column in a barometer? 5  What I Can Do Performance Task: Make a short poem about “Pressure in Everyday Life”. Note:  You may have you own title as long as within the topic.  You may add any creativity or even write your poem in calligraphy.  It is handwritten in an A4 bond paper. Enrichment Activity: Watch a video through YouTube link below entitled “Pressure Gases”, https://www.youtube.com/watch?v=NzKAJWTmlwg 6  Lesson Gas Laws 2 What’s In In lesson 1, you have learned about the definition of pressure, and the different units that can be used to measure and express pressure which are the atmospheric pressure (atm), millimeter of mercury (mmHg), pounds per square inch (psi), Pascal (Pa), and kilopascal (kPa). Moreover, you have also learned one unit to another unit of pressure, and able to show the solution for correct conversion. Pressure is one of the variables that describes the properties of gases, so in continuation, the next topic will help you learn about the other variables which are the Volume(V), Temperature (T), amount in moles (n) that describes the behavior of gases under certain condition and the laws that governs how it behaves. What I Need to Know Air is all around us, thus gases always involved in our daily activities, from breathing down to automobile tires or bicycle, balloons, and even lifeboats and vest. Life won’t be possible without this life-sustaining gas found in the atmosphere. Scientist have always been curious about how gases behaves. And how it is different compared to other states of matter. Investigations and experiments on the behavior of gases leads to the parameters or variables that used to describe the properties of gases aside from pressure, and these are volume, temperature, and the amount in moles. The relationship between variables are explained by Gas Laws. In addition, you will be able to use gas laws to determine pressure, volume, temperature of a gas under certain conditions od change. Then, use the ideal gas equation to calculate pressure, volume, temperature, or number of moles of a gas. 7  What’s New Graph Analysis Direction: Based on the given graph, analyze and infer the relationship of the properties of gases (volume, pressure, temperature, and moles). Write your answer at the sides of the graph. 8  What Is It Gas Laws governs the behavior of gases and describes the relationship of the following variables: Pressure, Volume, Temperature, and moles. The relationship among the variables are led and investigated by Robert Boyle, Jacques Charles, and Amedeo Avogadro, and the laws where named after them respectively. Boyle’s Law The law is named after its proponent, who is a British chemist, Robert Boyle. He emphasized the law correctly and stated that “The volume of a given amount of gas is inversely proportional to its pressure at constant temperature”. It means, as the volume increases, the pressure of the gas decreases, and vice versa, provided that the temperature remains the same. Thus, it is evident that the relationship between the two variables, volume and pressure is inversely proportional. Figure 1: Robert Boyle. Image source Boyle’s Law is expressed in this mathematical equation: In terms of proportion: V α 1/P (at constant amount and temperature) In terms of equation: V = k/P (at constant amount and temperature) PV=k or P1V1 = P2 V2 Where; P1 = initial pressure V1 = initial volume P2 = Final pressure V2 = Final volume Example: A 2.5 L container has a gas pressure of 4.6 atm. If the volume is decreased to 1.6 L. What will be the new pressure inside the container? Given: V1 = 2.5 L V2 = 1.6 L P1= 4.6 atm P2 = ? P1V1 = P2V2 , P2 = P1V1 / V2 = 1.6 atm (2.5 L) 1.6 L = 7.2 atm 9 Charles’ Law It is one of the gas laws and named after the French scientist Jacques Charles who formulated the law in 1897. This law states that “The volume of a given amount of gas is directly proportional to its absolute temperature and constant pressure.” It means that as the volume increases, the temperature also increases, and vice versa, provided that the amount of gas and the pressure is constant. The temperature should be expressed in Kelvin (K). Figure 2: Jacques Charles. Image source Charles’ Law is expressed in this mathematical equation: In terms of proportion: V α T (at constant amount and pressure) In terms of equation: V = kT (at constant amount and pressure) V / T =k or V1 / T1= V2 / T2 Where; V1 = initial volume T1 = initial Temperature V2 = Final volume T2 = Final Temperature Example: A 3.5 L flexible container holds a gas at 250 K. What will be the new volume if the temperature is increased to 400K at constant pressure? Given: V1 = 3.5 L V2 = ? T1= 250 K T2 = 400K V1 / T1 = V2 / T2 ; V2 = V1T2 / T1 = 3.5 L (400K) 250 K = 5.6 L 10 Avogadro’s Law The proponent of this law is named after Amedeo Avogadro, who is a notable Italian mathematical physicist. This law state that “The volume of a gas at a given temperature and pressure is directly proportional to the number of moles contained in the volume”. This law is based on Avogadro’s hypothesis that the same volume of two gases at constant temperature and pressure contain the same number of molecules. It means as the volume increases the amount of substance or the moles also increases, so the relationship is directly proportional. Keep in mind that a mole is related to the quantity of molecules in Figure 3: Amedeo Avogadro. Image source a substance. Avogadro’s Law is expressed in this mathematical equation: In terms of proportion: V α n (at constant temperature and pressure) In terms of equation: V = k n (at constant temperature and pressure) V / n =k or V1 / n1= V2 / n2 Where; V1 = initial volume n1 = initial number of moles of the gas V2 = Final volume T2 = Final number of moles of the gas Example: A 2.4 moles of gas occupies 60.0 L at a certain temperature. What volume will 3.7 moles of a gas occupy? Given: n1 = 2.4 moles n2 = 3.7 moles V1= 60.0 L V2 = ? V1 / n1 = V2 / n2 ; V1n2=n 1V2 V2 = V1 n2 / n1 = 60.0 L ( 3.7 moles) 2.4 moles = 92.5 L 11 Ideal gas Equation It is a single equation that sums up and combines the mathematical expression of Boyle’s Law, Charles’ Law, and Avogadro’s Law. PV = nRT Where; P = Pressure n= moles (refers to the amount of substance) V= Volume T= Temperature (express in Kelvin (K)) R = The universal gas constant (0.0821 atm.L / mol.K) The value of the universal gas constant (R) is the same anywhere and anytime. It can be calculated using the using the standard conditions of mole, pressure, volume, and temperature. The value can also be derived from the ideal gas equation as shown below. PV = nRT R = PV = 1.00 atm x 22.4 L nT 1.00 mole x 273 K R = 0.0821 atm. L mole.K Example: A 3.5 L container holds 0.45 moles of O2 gas at 300K. What is the pressure inside the container? Given: V = 3.5 L T = 300 K N = 0.45 moles P=? PV = nRT ; P = nRT V atm. L = 0.45 moles x 0.0821 mole.K x 300 K 1.5 L P = 3.17 atm 12  What’s More Calculations A. Direction: Calculate the given problems and use the gas laws to determine pressure, volume, or temperature of a gas under certain conditions of change. Show your solutions. Encircle your final answer. 1. The gas inside the tire has a volume of 20.00 L at a pressure of 5.00 atm. Calculate the pressure of the gas if its volume is reduced to 10.0 at the same temperature. 2. If 150.00 mL of N2 gas was collected at 760 torr, what is the new volume of the gas when the pressure is compressed to 740 torr at the same temperature? 3. At 300 K, the given amount of fluorine gas has a volume of 30.0 L. What will be the temperature if the gas occupies a volume of 25 L at constant pressure? 4. A certain gas sample has a volume of 40.00 L at 273 K. At constant pressure, the volume increase to 50.00 L. What will be the final temperature of the gas? 5. At 55.00 L a compressible container contains 5.00 moles of a certain gas. If 3.00 moles of a gas were added to the container, what will be its final volume? 13 B. Direction: Complete the following table and use the Ideal gas equation to calculate pressure, volume, number of moles, and temperature of a gas. Express your final answer in two (2) decimal places and show your solution below the table. Pressure (P) Volume (V) Temperature (T) Moles (n) 1. 5.00 atm 25.00L 273.15 K ____________ 2. ____________ 0.55 L 308 K 0.50 mol 3. 20.00 atm 30.00 L ___________ 25.30 mol 4. 15.00 atm __________ 370.00 K 3.00 mol 5. _________ 10.50 L 280.00 K 10.00 mol 14  What I Have Learned Picture Analysis Direction: Analyze the given picture and identify the appropriate gas laws that best describes the picture. 1. 2. 3. 4. 5. 15  What Is It Most of the gases encountered in the surroundings are mixtures. Mixtures are composed of different components. An example of a mixture is air which is a combination of primarily nitrogen and oxygen and other inert gases. Each individual component in air exert its own pressure, has its own volume, can have a temperature that is in thermal equilibrium with the other components, and also has its own molar amount. This just means that the ideal gas equation can also be used on mixtures of gases. Say for example, a constant-volume piston shown below contains a sample of flue gas, a by-product of combustion, which is composed of nitrogen (1), carbon dioxide (2), and carbon monoxide (3) at a constant temperature of 30°C. 1 1 2 1 2 3 2 1 3 From the situation above, the number of moles of each component can be interpreted as n1, n2, and n3 for nitrogen, carbon dioxide, and carbon monoxide, respectively, so that the total number of moles can be shown as: 𝑛𝑡𝑜𝑡𝑎𝑙 = 𝑛1 + 𝑛2 + 𝑛3 The pressure exerted by the mixture can then be calculated using the ideal gas equation: 𝑛𝑡𝑜𝑡𝑎𝑙 𝑅𝑇 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 = 𝑉 …where V is the volume of the container or in this case, the volume of the constant-volume piston. Substituting the two equations, the pressure of the mixture can be expressed as: (𝑛1 + 𝑛2 + 𝑛3 )𝑅𝑇 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 = 𝑉 And distributing the ideal gas constant and temperature: 𝑛1 𝑅𝑇 𝑛2 𝑅𝑇 𝑛3 𝑅𝑇 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 = + + 𝑉 𝑉 𝑉 16  As you may recall, the term nRT/V is equal to P which means that the terms in the right hand side of the equation equates to the pressure exerted by each individual component. 𝑛1 𝑅𝑇 𝑛2 𝑅𝑇 𝑛3 𝑅𝑇 𝑃1 = 𝑃2 = 𝑃3 = 𝑉 𝑉 𝑉 Pressures P1, P2, and P3 are called the partial pressure of each gas. Combining all the equations, it can be concluded that the pressure exerted by the mixture is the sum of the pressures exerted by each component. This is known as the Dalton’s Law of Partial Pressure. 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 = 𝑃1 + 𝑃2 + 𝑃3 The application of Dalton’s Law of Partial Pressure can help us learn about the composition of each component in terms of mole fraction of the component. 𝑛1 𝑅𝑇 𝑛𝑡𝑜𝑡𝑎𝑙 𝑅𝑇 𝑃1 = 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 = 𝑉 𝑉 Combining these two equations gives the following expression: 𝑃1 𝑛1 = = 𝑥1 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 𝑛𝑡𝑜𝑡𝑎𝑙 …where x1 is the mole fraction of component 1 in the mixture. Rearranging the above equation leads to: 𝑃1 = 𝑃𝑚𝑖𝑥𝑡𝑢𝑟𝑒 𝑥1 This means that the partial pressure of a component is equal to its mole fraction multiplied to the pressure exerted by mixture. What’s More A. Who’s Greater? Directions: Try to determine which column exerts greater partial pressure is greater by putting E on the blank if the column on the left is greater than the column on the right and putting Z on the blank if the column on the right is greater than the column on the left. Ptotal = 0.83 atm Ptotal = 0.95 atm 1. X1 = 0.23 X2 = 0.19 Ptotal = 14 psi Ptotal = 10 psi 2. n1 = 0.2 mol n2 = 12 mol ntotal = 0.3 mol ntotal = 16 mol 17  Ptotal = 20 kPa Ptotal = 0.95 atm 3. X1 = 0.87 X2 = 0.19 Ptotal = 101 kPa Ptotal = 110 kPa 4. n1 = 0.4 mol n2 = 5 mol ntotal = 1.2 mol ntotal = 14 mol Ptotal = 1.2 atm Ptotal = 110 kPa 5. n1 = 0.4 mol n2 = 5 mol ntotal = 1.2 mol ntotal = 14 mol Ptotal = 2.3 atm Ptotal = 3.4 atm 6. X1 = 0.23 X2 = 0.19 Ptotal = 0.83 atm Ptotal = 19 psi 7. X1 = 0.23 X2 = 0.19 Ptotal = 202 kPa Ptotal = 30 psi 8. n1 = 0.4 mol n2 = 5 mol ntotal = 1.2 mol ntotal = 14 mol Ptotal = 1.2 atm Ptotal = 3.4 atm 9. X1 = 0.5 X2 = 0.2 Ptotal = 6 MPa Ptotal = 5.3 MPa 10. X1 = 0.6 X2 = 0.5 B. Problem Solving Directions: In a separate sheet of paper, show your solution and encircle your final answer. 1. A sample of oxygen gas, which is saturated with water vapour, is kept in a 10- L vessel at 30°C and has a pressure of 758 Torr. If the pressure of the water vapour at this temperature is 31.8 Torr, what would be the pressure of the dry oxygen? 2. If the oxygen gas sample in #1 passed through a drier that decreased the pressure of the mixture to 750 Torr and the pressure exerted by the water vapour is only 80% of the saturated vapour pressure at the given temperature, what would be the pressure of the dry oxygen? 3. In a gas mixture composed of N2, Ne, and He, the partial pressure of N2 is 0.50 atm, that of Ne is 1.1 atm, and the total pressure is 2.4 atm. What is the partial pressure of He? 4. In a gas mixture composed of N2, Ne, and He, the partial pressure of N2 is 0.50 atm, that of Ne is 1.1 atm, and that of He is 0.80 atm. Calculate the mole fraction of each gas. 5. A gas mixture contains 2.5 mol N2 and 9.7 mol CO2, and has a pressure of 2.3 atm. What is the partial pressure of each gas? 18  What I Can Do Performance Task: Poster Making Draw and illustrate the three (3) laws of gases based on their real-life application in an A4 size bond paper. Enrichment Activity: Watch a video through YouTube link below entitled “The Ideal Gas Law”, https://www.youtube.com/watch?v=BxUS1K7xu30 19  Summary Gases are everywhere, it behaves differently from other states of matter. The properties of gases are described by its variables or parameters namely; pressure, temperature, volume, and the amount of substance or moles under some certain conditions. The relationship between the variables are govern by gas laws. Gas laws and categorized into three laws; Boyle’s Law, Charles’s Law, and Avogadro’s Law which are named after their proponents and scientist who observed such properties of gases. Boyle’s law describes that the relationship of pressure and volume is inversely proportional given that temperature is constant, for Charles’s Law, Volume and Temperature is directly proportional at constant pressure. Avogadro’s law explains the relationship between volume and the amount of substance (moles) is directly proportional when pressure and temperature is constant. Then, the variables are combined to form an ideal gas equation. Dalton’s Law of Partial Pressure tells us that the pressure of each component in a mixture is equivalent to its mole fraction multiplied to the total pressure exerted by the mixture. 20  Assessment: Post-Test MULTIPLE CHOICE. Directions: Read and understand each item and choose the letter of the best answer. Write your answers on the space provide before the number. __1. Which of the following description refers to pressure? e. It is the force exerted by colliding molecules per unit area of container walls. f. It refers to the force exerted by the wall. g. The force resulted from the molecules or particles in static. h. The resulting force from the bodies at rest or in equilibrium. __2. Which of the following is not a unit of pressure? b. Atm b. Torr d. mmHg d. none of the above __3. Which of the following refers to standard atmospheric pressure? e. Atm f. Torr g. mmHg h. Pa __4. One (1) atm is equal to what value of mmHg? e. 706 mmHg f. 273 mmHg g. 760 mmHg h. 101.3 kPa __5. The volume of a given amount of gas is inversely proportional to its pressure at constant temperature is stated by what law? e. Avogadro’s Law f. Charles’s Law g. Gay-Lussac Law h. Boyles Law __6. When volume on a gas goes up what happens to its pressure? e. stays the same f. goes down g. rises h. rises, then falls __7. Which of the following refers to the statement of Charles’ Law? e. The relationship of volume and pressure of a gas is inversely proportional. f. The relationship of volume and pressure of a gas is directly proportional. g. The relationship of temperature and volume of a gas is directly proportional. h. The relationship of temperature and volume of a gas is inversely proportional. __8. When the volume goes down the what happens to its temperature? e. rises f. goes up g. goes down h. rises, then falls __9. Which of the following gas laws describes the relationship of volume and moles? c. Boyle’s Law c. Charles’s Law d. Avogadro’s Law d. Ideal Gas Laws __10. Which of the following is the ideal gas equation? c. PV=NRT c. PV=nRT d. Pv=nrt d. pv=nRT 21  Key to Answers Pretest Lesson 1 What’s New What’s More What Have I Learned? 1. Defines as the amount of force exerted per unit area. It refers to the force exerted by colliding molecules per unit area of container walls. 2. a. Standard Atmosphere (atm)  It is commonly and widely used unit for pressure in chemistry. b. Torr (or mmHg)  mmHg means millimeter of mercury, where it represents the pressure exerted by a column of a mercury which exactly equals to atmosphere. c. Pounds per square inch (psi) The atmospheric pressure at sea level is 14.7 psi. d. kilopascal(kPa)  A kilopascal is equal to 1000 pascals (Pa). It is the standard unit for pressure. 3. 743 torr 4. 2.72 atm 5. 1500 kPa Lesson 2 What’s New Graph 1: A graph showing the relationship between volume and pressure, as stated by Boyle’s Law. Pressure and Volume is inversely proportional. As the pressure increases, the volume decreases, and vice versa. 22 Graph 2: A graph showing the relationship between volume and temperature, as stated by Charles’ Law. Volume and Temperature is directly proportional. As the volume increases, the temperature also increases. Graph 3: A graph showing the relationship between volume and moles (the amount of the substance), as stated by Avogadro’s Law. Volume and number of moles in a substance is directly proportional. What’s More (Gas Laws) A. B. What Have I Learned (Gas Laws) What’s More (Dalton’s Law) A. B. Post-test 23  References Commission on Higher Education, General Chemistry 1: Teaching Guide for Senior High, Manila, 2016. Department of Education Central Office, Most Essential Learning Competencies (MELCS), Manila, 2020. Department of Education, EASE/OHSP II Module 9: Gas Laws, Learning Resource Management Development Team, 2016. A. Mapa, T. Fidelino and L. Rabago, Chemistry Textbook in Science and Technology, Quezon City: SD Publications, 2001. "Clipart Library," [Online]. Available: http://www.clipart-library.com/free/balloon- clipart-transparent-background.html. [Accessed 6 July 2020]. [Online]. Available: https://www.firestonetire.ca/tire/weathergrip. [Accessed 6 July 2020]. [Online]. 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