Combined Gas Law.docx

Republic of the Philippines Department of Education Region V Division of Camarines Sur DON TEOFILO H. DILANCO MEMORIAL HIGH SCHOOL Cambalidio, Libmanan Camarines Sur S/Y 2018-2019

Detailed Lesson Plan

Combined Gas Law Date: March 05, 2019 Time allotments: 1 hour I.

II.

Objectives: At the end of 1 hour discussion, 75% of the students are expected to: 1. Identify the three Laws involve in Combined Gas Law. 2. Transform Combined Gas Law into an equation. 3. Value the importance of Combined Gas Law in real life application. Subject Matter: a) Topic: Combined Gas Law b) References:  Science Learner’s Module of Grade 10 by DepEd Republic of the Philippines  Integrated Science 2 by Estrella E. Mendoza  Microsoft Encarta 2009, 1993-2008 Microsoft Corporation c) Materials:  PowerPoint Presentation  Video Clips  Laptop and projector  Manila Paper and Pentel Pen  Activity sheets  Visual aids (Colored Materials - papers) d) Skills: Identifying, Interpretation, analyzing, comparing and developing scientific attitudes. e) Values integration: Understanding the laws of gases, will help us to deal with different situation by the involvement of gases. f) Teaching strategy: 5 E’s (engage, explore, explain, elaborate and evaluate) g) Concepts: The combined gas law combines the three gas laws: Boyle's Law, Charles' Law, and GayLussac's Law. It states that the ratio of the product of pressure and volume and the absolute temperature of a gas is equal to a constant. When Avogadro's law is added to the combined gas law, the ideal gas law results. Unlike the named gas laws, the combined gas law doesn't have an official discoverer. It is simply a combination of the other gas laws that works when everything except temperature, pressure, and volume are held constant. There are a couple of common equations for writing the combined gas law. The classic law relates Boyle's law and Charles' law to state: PV/T = k Where P = pressure, V = volume, T = absolute temperature (Kelvin), and k = constant. The constant k is a true constant if the number of moles of the gas doesn't change. Otherwise, it varies. Another common formula for the combined gas law relates "before and after" conditions of a gas: P1V1 / T1 = P2V2 / T2

I. TEACHING PROCEDURES Time Teaching Guide Teacher’s activity frame A. Preliminary Activities 1. Greetings Good Afternoon Class! 2. Prayers

3. Securing cleanliness

4. Checking attendance

Students Activity

Good Afternoon Ma’am!

Ok class, kindly stand up for our opening prayer. Joy, kindly lead us the prayer. In the name of the Father… (students reciting the daily prayer) of Class before we begin kindly pick up all the pieces of papers, plastics and candy wrappers that you see under your chair and arrange your chairs properly. (the students are picking the piece of paper and arranging their seats properly) of How many absent do we have today? Ok, Miss secretary please list down the name of the absentees. Yes ma’am.

5. Checking of Last meeting I gave you an Assignment assignment. Right? Ok, later we will check that assignment. B. Preliminary Activities 1. Recall Before we proceed to our new topic for this afternoon, who can recap what we have discussed last meeting? Yes, Ellen

Ma’am last meeting we have discussed about Gay Lussac Law.

Thank you! Ellen How about you Kharistel, what have you learn about GayLussac Law? In Gay-Lussac Law, it is said that the relationship between temperature and pressure is directly proportional meaning if the pressure increase the temperature increases too (vice versa). Very good Ellen! Is there any clarification or questions regarding our last topic? None ma’am! 2. Motivation

I want you to look to those pictures or sentences that I will show in PowerPoint presentation then identify what would our topic for this afternoon.

(Students will response) C. Lesson Proper 1. Presentation of Anyone who has an idea what is the topic our topic for this afternoon? Ma’am, our topic for this afternoon is all about Combined Gas Law.

2. Presentation of That’s right. So, this afternoon learning we will discuss about Combined objectives Gas Law. (The teacher post on the board the learning objectives) At the end of the discussion 75% of the students are expected to: 1. Identify the three Laws involve in Combined Gas Law. 2. Transform Combined Gas Law into an equation. 3. Value the importance of Combined Gas Law in real life application. 3. Unlocking difficulties

of Ok, today we will tackle what (All students will read the learning Combined Gas Law is, and the objectives aloud) importance of these. But, before that we must first unlock some definition of terms. Boyle’s Law

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Charle’s Law

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Gay-Lussac Law

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Combined Gas Law

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The volume of a gas is inversely related to its pressure at constant temperature. The volume of a gas is directly related to its temperature at constant pressure. The pressure of a gas is directly related to its temperature at constant volume. It states that the pressure and volume of a gas are inversely proportional to each other, but are both directly proportional to the temperature of that gas.

D. Methodology (5E’s) 1. Engage

1. Have you ever notice the warning label in the aerosol container? What is the temperature requirement for its storage? Have you seen an explosion of a can of this kind? The explosion of this container is also an application of Combined Gas Law. “The exposure to high temperature increases the kinetic energy of the gases causing an increase in the pressure due to the increased collision of the gases in the walls”. (The teacher will present a video clips) (Students will analyse the video presentation)

2. Explore

Before we proceed with our discussion, let’s have first an activity is called “Combined Gas Law – Egg cited”.

a) Pre-activity

I have here some materials needed for each group activity. What you are going to do is to perform the experiment. You’re going to describe the activity and answer the following questions, write it in (The students are listening attentively to the instructions given) manila paper. Here’s the rubrics on how to rate your output. (Criteria for the activity are presented in PowerPoint presentation) RUBRICS:  Correctness 1-4  Promptness - 1-4  Presentation of the output – 1-4 NOTE: That 4 is the highest score and 1 is the lowest score (students are analyzing the rubrics) (see the attached rubrics) I will group you into two (2) and you only have 10 minutes to do the activity. After that, somebody from your group will present your output. (The teacher will provide the materials needed by each group (The students will be grouped into for the group activity) three and will listen carefully as the teacher gives further instructions.) (After 10 minutes) Okay class, time is up. Post your work on the board.

b) Activity Proper

Group I: Combined Gas Law Group II: Combined Gas Law (Each group will present their work and choose a representative to present their output.)

(The teacher will give the corresponding points to each group based from the rubrics of the activity.)

a) Post-activity

Expected answer of students on their activity.

the Group I and II: Combined Gas Law

(The egg is placed inside the Erlenmeyer Flask) It explained the Combined Gas Law. How do you find the activity?

3. Explain

It was fun ma’am, interesting and we enjoy it.

Based on the activity, who can define what is Combined Gas Law? It is the combination of the three gas law. (Boyle’s Law, Charles Law and Gay Lussac’s Law) Very good answer. So, what are the differences of the three laws?

Boyle’s Law is inversely proportional to volume and pressure. Charles Law is directly proportional to volume and temperature and Gay Lussac’s Law is directly proportional to pressure and temperature. The activity you performed explained the combined gas law. To understand more, watch this video presentation.

As we understand the concept of Combined Gas Law. Let’s transform combined Gas Law into an equation.

(The students will analyze the short video presentation)

We mathematically expressed it as:

Take note class that only Kelvin is used in temperature.

Where: V1= initial volume of the gas V2 final volume of the gas P1= Initial pressure of the gas P2= final pressure of the gas. T1= Initial temperature of the gas T2= final temperature of the gas.

4. Elaborate

Try this! The volume of a gas at 27⁰C and 700 mmHg is 600 ml. What is the volume of the gas at -20.0⁰C Given: and 500 mmHg? V1 = 2.5 L P1 = 760 mmHg T1 = 25℃ V2 = 1.75 L P2 = 1140 mmHg T2 = ? Solution: V1 = 2.5 L P1 = 760 mmHg T1 = 25℃ + 273.15 = 298.15 K V2 = 1.75 L P2 = 1140 mmHg T2 = ? Formula : V1P1T2 = V2P2T1 Solution: V1 P1 T2 = V2 P2 T1 (25L) (760 mmHg) (T2) = (1.75L) (1140 mmHg) (298.15 K) 19,000( L)(mmHg)(T2) = 594,809.25 (L)(mmHg)(K) 19,000( L)(mmHg) = 19,000( L)(mmHg T2 = 31.306K

Formula :

V1P1 T1

=

V2P2 T2

Checking: (25L)(760 mmHg) = (1.75L) (1140 mmHg) 298.15 K) = (31.306 K) 63.73 = 63.73

The combined gas law has practical applications when dealing with gases at ordinary temperatures and pressures. Like other gas laws based on ideal behavior, it becomes less accurate at high temperatures and pressures. The law is used in thermodynamics and fluid mechanics. For example, it can be used to calculate pressure, volume, or temperature for the gas in clouds to forecast weather.

(Students will analyzed the applications of combined Gas Law).

III.

Evaluation: Using the equation of combined gas laws, V1P1T2 = V2P2T1 the answers are provided in the following problems: 1. Helium gas has a volume of 250 ml at 0⁰C at 1.0atm. What will be the final pressure if the volume is reduced to 100 ml at 45⁰C?

IV.

Assignments: 1. On a one half crosswise, cite the importance in understanding Combined Gas Law.

Prepared by:

Joycel A. Comia Teacher I