Acids and Bases
Suggested time allotment: 5 to 6 hours
MODULE
2
ACIDS AND BASES
In Module 1, you identified common properties of solutions using different methods. You learned how to report the amount of the components in a given volume of solution. You also found out that not all solutions are liquid. Some of them are solids and others are gases. Towards the end of the module, you investigated the factors that affect how fast a solid dissolves in water. Most of the solutions you studied in Module 1 form two classes or groups of materials that are related to each other and are important in daily life. They have common properties that can easily be identified. What do you think are common properties among vinegar, calamansi juice, and soft drinks? What are common among liquid sosa (drain cleaners), soaps, and detergents? Which among these are called acids? Which are classified as bases? In this module, you will investigate the properties of acids and bases using an indicator, a dye that changes into a specific color depending on whether it is placed in an acid solution or in a basic one. Aside from knowing the uses of acids and bases, you will also find out the action of acids on metals and think of ways to reduce the harmful effects of acids. Knowing the properties of acids and bases will help you practice safety in handling these solutions, not only in this grade level, but in your future science classes.
How acidic or basic are common household solutions? Does water from different sources have the same acidity? What is the effect of acid on some familiar metals?
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Activity 1 How can you tell if a solution is an acid or a base?
Acids and bases are all around us. How will you know if a solution is an acid or a base? In this activity, you will distinguish between acids and bases based on their color reactions to an indicator. An indicator is a dye that changes into a different color
MODULE
2
ACIDS AND BASES
In Module 1, you identified common properties of solutions using different methods. You learned how to report the amount of the components in a given volume of solution. You also found out that not all solutions are liquid. Some of them are solids and others are gases. Towards the end of the module, you investigated the factors that affect how fast a solid dissolves in water. Most of the solutions you studied in Module 1 form two classes or groups of materials that are related to each other and are important in daily life. They have common properties that can easily be identified. What do you think are common properties among vinegar, calamansi juice, and soft drinks? What are common among liquid sosa (drain cleaners), soaps, and detergents? Which among these are called acids? Which are classified as bases? In this module, you will investigate the properties of acids and bases using an indicator, a dye that changes into a specific color depending on whether it is placed in an acid solution or in a basic one. Aside from knowing the uses of acids and bases, you will also find out the action of acids on metals and think of ways to reduce the harmful effects of acids. Knowing the properties of acids and bases will help you practice safety in handling these solutions, not only in this grade level, but in your future science classes.
How acidic or basic are common household solutions? Does water from different sources have the same acidity? What is the effect of acid on some familiar metals?
__________________________________________________________________________
Activity 1 How can you tell if a solution is an acid or a base?
Acids and bases are all around us. How will you know if a solution is an acid or a base? In this activity, you will distinguish between acids and bases based on their color reactions to an indicator. An indicator is a dye that changes into a different color
References: and Links Brady, J.E. & Senese, F. (2004). Chemistry: Matter and its changes, 4th edition. River Street Hoboken, NJ: John Wiley & Sons, Inc Bucat, R.B. (Ed.) (1984). Elements of chemistry: Earth, air, fire & water, Volume 2. Canberra City, A.C.T., Australia: Australian Academy of Science. Bucat, R. B. (Ed.) (1983). Elements of chemistry: Earth, air, fire & water, Volume 1. Canberra City, A.C.T., Australia: Australian Academy of Science. Burns, R. A. (1999). Fundamentals of chemistry, 3rd edition. Upper Saddle River, N.J. Prentice-Hall, Inc. Grade 7 Science: Matter Diversity of Materials in the Environment 16 Elvins, C., Jones, D., Lukins, N., Miskin, J., Ross, B., & Sanders, R. (1990). Chemistry one: Materials, chemistry in everyday life. Port Melbourne, Australia: Heinemann Educational Australia. Gallagher, R. & Ingram, P. (1989). Co-ordinated science: Chemistry. Oxford, England: Oxford University Press. Heffner, K. & Dorean, E. (n.d.) Must it rust? The reaction between iron and oxygen. Retrieved Feb 16, 2012 from http://www.haverford.edu/educ/knight-booklet/mustitrust.htm Heyworth, R. M. (2000). Explore your world with science discovery 1. First Lok Yang Road, Singapore. Pearson Education South Asia Pte Ltd. Hill, J.W. & Kolb, D.K. (1998). Chemistry for changing times, 8th edition. Upper Saddle River, NJ: Prentice Hall. Philippines. Department of Education. (2004).Chemistry: Science and technology textbook for 3rd year. (Revised ed.). Quezon City: Author. Grade 7 Science: Matter Diversity of Materials in the Environment 17