Friday, October 07, 2011
Human Nature
https://docs.google.com/leaf?id=0B9UKBg4ieVcSNGVlYjZhNDYtNGQzYS00MDM2LWI2MTgtZjY4NjI2NGE5NjY2&hl=fil
Friday, September 30, 2011
Lesson Plan in Naming and Writing Chemical Formulas
Lesson Plan in Chemistry
I. Objectives: In the course of the discussion, the third year students with least 80% accuracy are expected to:
A. name chemical compounds;
B. write chemical formulas, and
C. tell the importance of knowing the names and chemical formulas of a compound.
II. Subject matter: Naming chemical compounds, polyatomic ions and writing its chemical formulas.
Science concept: Chemical Formula is the shorthand representation for compounds.
Science Processes: Observing, communicating, analyzing
Values Integration: Participation
References: Chemistry; Magno et. al; pp. 149- 154
Chemistry; Mendoza et al; pp. 141- 145
Chemistry; Pili et. al; pp. 129- 135
Materials: box, salt, power point presentation
III. Procedure:
A. Motivation:
Through a “name game” the students will guess the thing inside the box through the clues given by the teacher. But before the game, the teacher will ask and a question.
· Why do we name things?
We name things In order for us to identify things easily.
· Let us know how you are familiar with things. You going to guess what’s inside the box through the clues that I’ll be giving to you.
· It is a colorless substance with a coarse texture. You can break or pound it into pieces but it can still retained the satisfaction it gives for every human being.
· You can always find it in the kitchen but it can also be found in your favorite beaches. It is just a very simple things yet it plays a very important role in our daily life.
· It can serve as an additive or as a preservative. It gives flavor to your flavor but too much of it can cause a malfunction in your kidney.
B. Presentation:
· What is inside the box?
· What is the chemical name for salt?
· What is its chemical formula?
· How does it get its name and chemical formula?
C. Discussion:
In writing chemical formula we need to follow these rules:
Writing formulas
Steps:
1. Write the symbols for the ions.
2. Crisscross the numbers and write them as subscripts.
A. Binary compounds
It consists of two elements which are formed by metals and non-metals.
Examples:
· K+ and Cl- KCl
· Ca2+ and Br- CaBr2
· Mg2+ and N3- Mg3N2
Exercises:
Write the formula for the following:
1. Strontium fluoride
2. Calcium sulfide
3. Calcium phosphate
Naming Formulas
1. In naming binary compounds containing metals with fixed oxidation number, the metal is named first, followed by the nonmetal with the ending –ide.
Example:
Ca3N2 - calcium nitride
Exercises:
1. CaBr2 4. KCl
2. Mg3N2 5. Na2O
3. Al2S3
2. In naming binary compounds containing metals with variable oxidation numbers, the oxidation number must be specified.
Two types of naming system:
1. Stock system – the oxidation number is indicated by Roman numeral in parentheses.
2. Classical system – the suffixes –ous and -ic are used to denote the lower and higher oxidation states.
Cu2+ O2- Cu2O
Copper (I) oxide
Cuprous oxide
Exercises:
1. Fe2+ and Cl- 4. Pb2+ and I-
2. Sn4+ and F- 5. Hg2+ and Br-
3. Cu2+ and O2-
A. Binary compounds containing two non-metals
Prefixes are used
CO – carbon monoxide
CO2 – carbon dioxide
Exercises:
1. Name the following compounds
1. NO 4. P2O5
2. SO2 5. PCl5
3. CCl4
2. Write the chemical formulas of the following:
1. Nitrogen dioxide 4. sulfur trioxide
2. Dinitrogen trioxide 5. Diphosphorus pentoxide
3. Carbon disulfide
a. Metals with Polyatomic Ions
· Polyatomic ion is a stable group of atoms that carries an overall electrical charge.
· Parentheses are placed around the polyatomic ion and subscript is written just after the close parenthesis whenever a multiple polyatomic ion is necessary.
Mg2+ OH- Mg(OH)2
· Parentheses are not used when single polyatomic ion is present.
KKClO3 CaCO3 NaHCO3
Exercises:
Write the correct formula for
1. Strontium bicarbonate 4. Magnesium phosphate
2. Ammonium nitrate 5. Copper (III) carbonate
3. Iron (III) sulfate
Give the name of the following:
1. K2CrO4 4. FeSO4
2. Zn(NO3)2 5. Sn(OH)4
3. CuClO3
b. Acids
1. Binary
Hydrogen and a Nonmetal
o The word hydrogen comes first; then the second word is made by affixing the
suffix –ide to the root word of the nonmetal.
HCl hydrogen chloride
o When these substances are dissolved in water, they become aqueous acids. The prefix hydro is attached to the root word of the nonmetal and the suffix –ic is added. The word acid becomes the last term.
H2S (aq) hydrosulfuric acid
HCl (aq) hydrochloric acid
2. Tertiary/ ternary/ oxyacids
o -ite – ous acid phosphorous acid (H3PO3)
o -ate – ic acid Sulfuric acid (H2SO4)
c. Bases –(OH)
Fe(OH)2 - ferrous hydroxide
Mn(OH)3 – manganic hydroxide
Sn(OH)2 – Tin (II) hydroxide
IV. Evaluation:
In a 1/2 sheet paper, answer the following questions:
A. Write the formula of the following compounds:
1. Aluminum oxide
2. Zinc oxide
3. Nitrogen disulfide
4. Iron(II) chloride
5. Ferric sulfate
6. Sodium phosphate
7. Calcium hydroxide
8. Cupric oxide
9. Dinitrogen tetroxide
10. Magnesium hydroxide
B. Name the following compounds
1. MgF2
2. SnO2
3. SiO2
4. BrF5
5. SF4
V. Assignment:
Complete the following table by writing the formula of the compounds formed by the combination of he given positive and negative ion. Write it in ½ sheet of paper.
-/+ ion Cl- S2- CO32- (PO4)3-
1. Mg2+
2. Al3+
3. Hg+
4. (NH4)+
Gas Laws
Gases
Properties of Gases According to Kinetic Molecular Theory
1. All gases are made up of tiny particles called molecules.
2. The molecules are small in relation to the distances between them.
3. Gas molecules are in constant state of motion and move in straight lines.
4. Gas molecules are perfectly elastic.
5. The velocity and kinetic energy of the molecules changes with the temperature, with increasing temperatures, and decreasing with decreasing temperatures.
6. The average energy possessed by the particles is the same regardless of the mass.
Gas Laws
1. Boyle’s Law – pressure and volume
V α where α means proportional
PV = K where K is constant
| [ P1V1 = P2V2 ] |
V1 = the volume at pressure 1 P1
V2 = the volume at pressure 2 P2
2. Charles’ Law – Volume and Temperature
“At constant pressure, the volume of a given mass is directly proportional to the absolute temperature.”
*If the absolute temperature is doubled, the volume of gas is doubled.
V α T or V/T = K
| V1/ T1 = V2/T2 |
3. Avogadro’s Law
“The volume of a gas is directly proportional directly related to the number of moles of a gas when the temperature and pressure are not changed.”
V α n
V = Kn
V/N = K
4. Gay Lussac’s Law – Temperature and Pressure
“The pressure of the gas is directly related to its Kelvin temperature.”
*An increase in temperature increases the pressure of a gas and a decrease in temperature decreases the pressure of the gas as long as the volume and number of moles of the gas remains constant.
P α T where V = constant
P = KT
| P/T = K |
5. The Combined Gas Law
“To determine the new volume when both the temperature and pressure are changed, we have to consider how the volume will change as temperature changes when pressure is held constant.”
PV/T= C
| P1V1/T1 = P2V2/T2 |
6. Ideal Gas Law
Boyle’s Law: V α (where n and T constant)
Charles’ Law: V α T (n and P constant)
Avogradro’s Law: V α n (P and T constant)
Combining the three laws, you will get:
V α nT/P
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