General- Chemistry Q1 Mod8 Write-and-Balance-Chemical-Equation PDF

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GeneralChemistry 1Quarter 1 - Module 8Writing and BalancingChemical Equations11What I Need to Know?This module was written to guide you on writing and balancing chemicalequations properly and correctly. Gaining the skill on wr iting and balancingchemical equations, you can pr edict the product when ...

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11 General Chemistry 1 Quarter 1 - Module 8 Writing and Balancing Chemical Equations

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What I Need to Know?

This module was written to guide you on writing and balancing chemical equations properly and correctly. Gaining the skill on writing and balancing chemical equations, you can predict the product when two or more substances react to one another as well as the correct number of atoms that will combine or breakdown. The scope of this module covers many different learning situations where students could relate their personal experiences on chemical reactions and chemical equations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course. But the order in which you read them can be changed to correspond with the textbook you are now using. After going through this module, you are expected to: 1. write and balance chemical equations, (STEM_GC11CRlf-g-37).

What I Know? (Crit (Critica ical Thi Think nkin ing) g)

To check your prior knowledge about the topic, and to solicit the questions that you want to know about it, fill in the Know and Want to know components of the Know-Want to know- Learned (KWL) chart properly and correctly. For the Know component, you may write word/s or sentence. For the want to know component, state your responses in interrogative or question form. You may list as many responses as you want for each component. Write your responses on a separate

sheet of paper. Topic Chemical Equations

Know

KWL Chart Want to know

Learned

Guide Questions 1. Based from what you have written on the Know component of the chart, what do you know about chemical equations? 2. If you were to think of a question that you want to ask about chemical equations, what question would that be?

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HOLD ON AMIGO!!! DIRECTION: After you have filled-in the K and W components of the chart and answered the guide questions, answer now the diagnostic assessment below within 10 minutes.

PRE-TEST Read and answer each statement carefully then write the letter of the best answer on a separate sheet of paper. 1. Which of the following changes would you consider to be a chemical change? A. Candle wax solidifies when it is cooled. B. Baking soda is combined with vinegar C. Ice melts. D. Paper turned into pieces. 2. All of the following are chemical reactions EXCEPT ___ A. burning of paper B. potassium fluoride and calcium nitrate are mixed. C. sodium hydroxide is added to nitric acid D. freezing of potassium nitrate solution. 3. The correct coefficients for the equation KClO 3 A. 2, 2, 3 B. 3, 2, 2

KCl + O 2 are ____ C. 2, 3, 2 D. 2, 1, 3

4. Balancing a chemical equation involves ____ A. adjusting the subscripts B. adjusting both subscripts and coefficients C. adjusting the coefficients D. adjusting the masses of reactants and products 5. What is the meaning of used in a chemical equation? A. yields B. reacts with C. heat is applied

D. gas

HOLD ON AMIGO!!! DIRECTION: Rest for 1 minute then you may start reading the lesson 1 below about the chemical equations.

Lesson 1

Chemical Equations

The water we drink every day, the sugar found in bread, the carbon dioxide gas produce from burning a piece of paper are examples of compounds which are being produced as the result of chemical reactions. These chemical reactions can be easily analyzed if they are written through chemical equations. Knowing the 3

process of expressing chemical reactions through chemical equations will give us full understanding on how elements or compounds combined or broken down to form new substances. This module will discuss the process of expressing the chemical reactions through words equations and balanced chemical equations properly and correctly.

What’s In? LET US HAVE SOME FUN! Equation Analysis. Analyze the equation below then answer the corresponding guide questions.

2H2O(l)

2H2(g) + O2(g)

Guide Questions 1. What is the equation all about? 2. What are the substances involved in the equation?

HOLD ON AMIGO!!! DIRECTION: After you analyze the given equation and answered the guide questions, let us proceed to what’s new. Read the direction carefully.

What’s New? (Communication) IMPORTANT VOCABULARY WORDS Read the description of important terms that you will encounter in this module.

VOCABULARY WORD

MEANING

1. Reactants

Substances involved before a chemical reaction

2. Product

Substance produced after a chemical reaction.

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HOLD ON AMIGO!!! DIRECTION: After finding out the meaning of important terms that you will encounter as you read the next part, make time to read the chemical equations below thoroughly.

What is Chemical Reaction and Chemical Equation? Chemical Reaction, Word Equation and Chemical Equation Chemical Reaction is a process in which one or more substances are changed into new substance with different physical and chemical properties. While Chemical Equation is the shorthand for describing the course of chemical reaction wherein the reactants are always written before the reaction or on the right side of the equation while the product is on the left side of the equation. A Word Equation describes a chemical change using the names of the reactants and products.

How to Write and Balance a Chemical Equation? In writing and balancing the chemical equations, important symbols must be remembered. Below are the common symbols used in writing and balancing chemical equations. SYMBOLS

1.

,

or

2. ( g ) or (

) means gas

=

means separates the reactants from the products.

3. ( l ) means liquid 4. ( s ) or (

) means solid

5. (aq) means aqueous, dissolved in water 6. 7.

or Pt

Heat

means heat is applied

means use as catalyst

Beside from the different symbols to be used in writing and balancing the chemical equations, there are special names of compounds that must be

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considered as well as whether a compound is diatomic. Below are the common names of some compounds. Name

Formula

Water

H O 2

Ammonia

NH 3

Methane

CH 4

Nitrous oxide

N O 2

Nitric oxide

NO

Hydrochloric acid

HCl(aq)

Nitric acid

HNO (aq) 3

Acetic acid

HC H O (aq) 2

Sulfuric acid

3

2

H SO (aq) 2

Carbonic acid

4

H CO (aq) 2

Phosphoric acid

3

H PO (aq) 3

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Important Steps in Solving the Formula Mass of a Compound In writing and balancing the chemical equations, do the following steps below. We will use the sample problem as an example.

Nitrogen gas reacts to Hydrogen gas to produce Ammonia. Step 1. Convert the given problem into a word equation. Nitrogen gas + Hydrogen gas

Ammonia

Step 2. Convert the word equation into a chemical equation. N

+ H 2(g)

NH 2(g)

3(g)

Note that there is subscript written after the chemical symbol of Nitrogen at the reactant side of the equation is 2 while the hydrogen is 2 as well. This is 6

because both nitrogen gas and hydrogen gas are diatomic substance. Carbon, Hydrogen, Oxygen, Nitrogen and other elements are diatomic substance. At the product side, the chemical formula of ammonia is NH 3 .

Step 3. Balance the given chemical equation written in the step 2 by adding coefficient after the chemical symbol or chemical formula. N

+ 3H 2(g)

2NH 2(g)

3(g)

To explain how we came up with this balanced chemical equation, let us refer the chemical equation in step 2. Let us determine the number of atoms of each element in the reactant side and in the product side. Look at the diagram below showing the subscript written after the chemical symbols and chemical formula in the chemical equation. Reactant side 2 2

Element N H

Product side 1 3

As you can see, the number of nitrogen atom in the reactant side is 2 while in the product side is 1 as shown by their subscript. For the hydrogen atoms, there are 2 atoms at the reactant side and 3 atoms for the product side. So, to balance the number of atoms at the reactant side and product side, coefficient is added before the chemical symbol or the chemical formula as indicated inside the parenthesis. Reactant side 2 6 = (3) 2

Element N H

Product side 1 (2) = 2 3 (2) = 6

PRACTICE EXERCISE : Problem Solving Water produces Hydrogen gas and Oxygen gas when subjected to electrolysis. Step 1. Convert the given problem into a word equation.

Step 2. Convert the word equation into a chemical equation.

Step 3. Balance the given chemical equation written in the step 2 by adding coefficient after the chemical symbol or chemical formula.

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HOLD ON AMIGO!!! Did you understand what you have read about writing and balancing the chemical equations? If yes, let us proceed to the mini-performance task. You are about to perform the procedure as instructed in the mini-performance task. Read and follow the procedure carefully. Good luck!

Mini-Performance Task (Collab (Collaboration) oration) Activity 1 – CHEMICAL EQUATION COMIC STRIP Procedure 1. Prepare bond paper, pen, coloring materials and ruler. 2. Given a set of problem on chemical reactions, choose 1 that you want to present before your teacher, make a comic strip that will explain how to solve your chosen problem on chemical reaction. Show the word equation, chemical equation and the balance equation in your comic strip. Add design that you want. 3. Explain your chemical comic strip before your classmates.

Output Presentation CHEMICAL EQUATION COMIC STRIP

Written by: _______

SET OF PROBLEMS 1. Magnesium reacts with Nitrogen gas to produce Magnesium nitride.

2. Chlorine gas reacts with Lithium bromide to produce Lithium chloride and bromine gas.

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Questions 1. What is the word equation and the balanced chemical equation of your chosen problem? 2. Did you find the comic strip making difficult to do? Why?

What I Have Learned? (Critical Thinking) You have to fill in the L component of the KWL chart to generalize the things they have learned about the topic. KWL Chart Topic Know Want to know Learned Chemical I have learned that Equations ….

HOLD ON AMIGO!!! After you have filled-in the L component of the chart, proceed now to the what I can do.

What I Can Do? (Character Character and Creativity tivity)) WORK IN PROGRESS Added task to you. Look for a product found at your home. Identify 1 chemical formula as written on its label then determine its formula mass as well as the uses.

HOLD ON AMIGO!!! Congratulations Mi Amigo! You are almost done in this module. Let us do the last part which is the assessment.

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Assessment (Criti (Critical cal Thinking) POST-TEST I. Multiple Choice Read and answer each statement carefully then write the letter of the best answer on a separate sheet of paper. 1. The end or final materials in a chemical reaction is known as ___ A. reactants B. product C. quotient

D. substance

2.What is the meaning of + used in a chemical equation? A. yields B. reacts with C. heat is applied

D. gas

3. In the reaction CH 4 + 2 O 2 CO 2 + 2 H 2 O, oxygen gas is ____ A. subscript B. product C. reactant

D. coefficient

4. Which equation is correctly balanced? A. C + O 2 2 CO B. C + O 2 CO 2

C. C + O 2 D. 2 C + O

5. In the equation 2 C 2 H 2(g) + 5 O dioxide is ___ A. 2 B. 5

C. (g)

CO 2 CO

4 CO 2(g) + 2 H 2 O (l), the coefficient for carbon D. 4

II. Problem Solving

Copper reacts with oxygen gas to produce copper oxide Step 1. Convert the given problem into a word equation.

Step 2. Convert the word equation into a chemical equation.

Step 3. Balance the given chemical equation written in the step 2 by adding coefficient after the chemical symbol or chemical formula.

HOLD ON AMIGO!!! Congratulations Mi Amigo!!! We are done in this module. You may now proceed to the next module. See you next time.

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REFERENCES

Mendoza E. and Religioso T. (2008). Chemistry Laboratory Manual. Phoenix Publication Mendoza E. (2003). Chemistry Textbook. Phoenix Publication

Acknowledgements Writer: Gary R. Ramos, MAT-GS Editors: Ma. Teresa M. Chico- PSDS, Rosalina Aranzamendez- PSDS and Ma. Victoria Santos- PSDS Reviewers: Amalia C. Solis- EPS, Rebecca M. Roxas- EPS and Lucita A. Gener- EPS Management Team: Maria Magdelema M. Lim- Schools Division SuperintendentManila, Aida H. Rondilla- Chief Education Supervisor, Lucky S. Carpio- EPS and Lady Hannah C. Gillo, Librarian II- LRMS 11

ANSWER SHEET Module 8 - Writing and Balancing Chemical Equations Name: ______________________________ Grade/ Sec. ____________________ Score: ___ Teacher: ____________________________ School: _________________________ Date: ____ General Direction: Write your answers here from Pre-Test to Post-Test including the answers in the activities. Detach and submit this part to your teacher upon his/her direction which usually given after you have completed this module. KWL CHART Topic Chemical Equations

PRE-TEST 1.

Know

2.

POST-TEST I. 1. 2. II. II. Problem Solving

Want to know

Learned

3.

4.

5.

3.

4.

5.

Copper reacts with oxygen gas to produce copper oxide Step 1. Convert the given problem into a word equation.

Step 2. Convert the word equation into a chemical equation.

Step 3. Balance the given chemical equation written in the step 2 by adding coefficient after the chemical symbol or chemical formula.

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PRACTICE EXERCISE : Problem Solving Step 1. Convert the given problem into a word equation.

Step 2. Convert the word equation into a chemical equation.

Step 3. Balance the given chemical equation written in the step 2 by adding coefficient after the chemical symbol or chemical formula.

Activity 1- CHEMICAL EQUATION COMIC STRIP Output Presentation

Answer to the Questions 1. ________________________________________________________________________ ________________________________________________________________________ 2. ________________________________________________________________________ _________________________________________________________________________

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