Form 4 Chemistry Textbook PDF

CHAPTER 1 Introduction to Chemistry Keywords Chemistry Chemical technology Scientific method Personal protective equipment Safety in the laboratory Management of laboratory accidents What wi...

CHAPTER 1 Introduction to Chemistry Keywords Chemistry Chemical technology Scientific method Personal protective equipment Safety in the laboratory Management of laboratory accidents What will you learn? 1.1 Development in Chemistry Field and Its Importance in Daily Life 1.2 Scientific Investigation in Chemistry 1.3 Usage, Management and Handling of Apparatus and Materials 2 Bulletin Chemistry helps us to understand matter and the reactions that they go through. Lately, the field of chemistry, especially nanochemistry has been developing rapidly. Nanochemistry focuses on the learning and knowledge of synthesis and properties of particles in nanoscale (as tiny as 10–9 m). In this field, chemists study the properties and uniqueness of the atoms and molecules in nanoscale. Nanochemistry combines nanotechnology, biotechnology, chemistry, biology, physic and mathematic into one single field. The discovery of nanochemistry has benefited humans tremendously, including in the field of medicine, health, agriculture, electronics, sources and energy, manufacturing industry and others. Knowledge in chemistry is the basis for mastering nanochemistry. All applications in the world of nanochemistry begin with the knowledge of chemistry learned at school. Therefore, mastering the fundamental concepts of chemistry in secondary school is the beginning of the expansion of knowledge related to chemistry. What is the meaning of chemistry? What are the careers that require the knowledge of chemistry? What are the correct methods to store chemicals in the laboratory? 3 THEME 1 The Importance of Chemistry 1.1 Development in Chemistry Field and Its Importance in Daily Life Based on Figure 1.1, what do you understand about chemistry? g Learnin tandard S Wow, the fireworks At the end of the lesson, look beautiful! How Fireworks look attractive pupils are able to: does it produce so especially at night. The 1.1.1 State the meaning many attractive attractive colours are caused of chemistry colours? by the mixture of chemicals 1.1.2 State examples of in the fireworks. What is chemicals commonly chemistry? used in daily life 1.1.3 Generate ideas on the development of chemistry field and the contributions of chemical technology towards mankind 1.1.4 State examples of careers related to chemistry field Figure 1.1 Fireworks and chemistry Activity 1.1 Century Discussing the meaning of chemistry based on students’ understanding 21st Skills 1. Carry out the Round Table activity. 2. Take turns to state the meaning of chemistry according to your understanding on a piece of blank paper based on: (a) The science knowledge that you have learned from Form 1 to Form 3 (b) Your experience outside the classroom 3. Present your group findings to your classmates. Meaning of Chemistry Chemistry is a field of science that studies the structures, properties, Father of Arabic compositions and interactions between matters. Learning of chemistry chemistry is not limited to chemicals found in the laboratory but also substances commonly found in daily life such as salt and soap. Chemistry helps us http://bit. ly/2qruQIF to understand matter around us. The word chemistry originated from the Arabic word ‘al-kimiya’. Carry out Activity 1.2 to study the origin of the word chemistry and its meaning. 4  Introduction to Chemistry CHAPTER 1 Activity 1.2 Century Collecting and interpreting the origin of the word chemistry and 21st Skills its meaning 1. Carry out the Think-Pair-Share activity. 2. Surf the Internet or refer to reading materials from various printed media to gather information and discuss the following issues: (a) Origin of the word chemistry (b) Meaning of chemistry 3. Present your group discussion results in multimedia form in front of your class. Chemicals in Daily Life Drugs contain All substances around us are made up of chemicals. The activities chemicals that we carry out daily involve chemical reactions as well. Figure 1.2 http://bit. shows the chemicals commonly used in foods, medicine, agriculture ly/2Mx4M7B and industries. Food Medicine als in daily l Preservative emic ife Antibiotic Colouring Ch Antiseptic Flavouring Vitamin Antioxidant Chemotheraphy Stabiliser Analgesic Herbicide Agriculture Industry Herbicide Paint Pesticide Polymer Fungicide Glass Fertiliser Ceramic Hormone Detergent Colouring Alloy Figure 1.2 Commonly used chemicals 5 THEME 1 The Importance of Chemistry The Development in Chemistry Field and the Contributions of Chemical Technology Researches in various chemical fields are constantly being carried out covering various disciplines. For examples, biochemistry, botany and forensics which require chemical knowledge to solve problems. The need for chemical technology to solve problems spurs the development of chemical technology. Technologies used in the 60s and 70s might not be suitable to be applied in this era. Based on your knowledge, what are the contributions of chemical technology to mankind? Carry out Activity 1.3. Activity 1.3 Century 21st Skills Searching for information and making a poster 1. Carry out the Gallery Walk activity. 2. Gather information on the following aspects: (a) Contribution of chemists (b) Development of chemical technology (c) Careers in the field of chemistry (d) Chemicals in daily life 3. Prepare the results of your group in an attractive poster. 4. Display your group’s results in the class. 5. Each group has to move around to look at the other groups’ posters. Write your comments about the results of the other groups on sticky notes and paste them on the posters. Bread with nanocapsules Food preservation using nanotechnology Food preservation Food preservation with by freezing salt or sugar Food preservation using nanotechnology http://bit.ly/2OKV8jj Figure 1.3 Development of technology in food preservation 6  Introduction to Chemistry CHAPTER 1 Careers Related to Chemistry In the era of rapid industrial development, most careers require knowledge in chemistry. For example, careers in the cosmetics, pharmaceutical, biotechnology, nanotechnology and green technology fields are shown in Figure 1.4. Examples of careers: Examples of Biotechnology careers: researcher Pha Doctor gy rm Biomedical nolo ac Pharmacist engineer e ch eu t ot i ca Bi l Nanotec Examples of tics FIELDS careers: sme Cosmetic hno Co chemist log Cosmetic y consultant Examples of careers: Green Nanotechnology technology engineer Examples of careers: Food scientist Green technology chemist Engineer Figure 1.4 Several careers related to chemistry Activity 1.4 Century Role-playing activity on careers in the field of chemistry 21st Skills CT 1. Carry out the Role-Play activity. 2. Gather information from suitable reading resources or websites on careers in the field of chemistry. 3. Assign the members of the groups to various careers. 4. Prepare the acting script and suitable props. 5. Present your group’s act in front of your class. 7 THEME 1 The Importance of Chemistry TestYourself 1.1 1. What is meant by chemistry? 2. List out five types of chemicals used in daily life. 3. Give one example of development of chemistry in industries. 4. List out at least three careers related to chemistry in the following situations: (a) Searching for an antidote for dengue fever (b) Producing palm trees with a high content of oil 1.2 Scientific Investigation in g Chemistry Learnin tandard S A scientific investigation is a scientific method used in solving At the end of the lesson, problems in science. Generally, a scientific investigation begins pupils are able to: with the observation of a problem. Look at Figure 1.5 and identify 1.2.1 Design an experiment to test a hypothesis the problem that occurs. We can carry out an investigation to solve 1.2.2 Investigate through the problem by using a scientific method. experiment the effect of temperature on the solubility of salt in water using a scientific method Mom, I have been stirring this salt for a long time. Why is there still salt in the solution? Why isn’t the salt dissolving? Boys, try adding some hot water into the salt solution. Figure 1.5 The solubility of salt in hot water Try to recall the steps in a scientific method that you have learned in Form 1. 8  Introduction to Chemistry CHAPTER 1 Scientific Method Scientific method is a systematic method used by scientists or researchers to solve problems related to science. This method involves several general steps to solve a problem using the correct methods. Making Using senses of sight, hearing, touch, taste or smell to gather information about observations an object or a phenomenon taking place. Making an Using data collection and past experience to make a conclusion and inference explanation about an event. Identifying Asking questions based on the inference made. the problem Making a general statement about the relationship between a manipulated Making a variable and a responding variable to explain an event or observation. This hypothesis statement can be tested to prove its validity. Identifying the Identifying the manipulated variable, responding variable and fixed variables variable(s) in an experiment to test the hypothesis that is formed. Controlling the In an investigation, a variable is manipulated to observe its relationship with variables the responding variable. Simultaneously, other variables are fixed. Determining the materials and apparatus to be used, procedure of the Planning an experiment, method of collecting data and the ways to analyse and interpret experiment the data. Collecting Making observations or measurements and recording the data systematically. data Organising and interpreting the data collected. Data can be interpreted Interpreting through calculations, graphs or charts to find and determine the relationship data between the variables. Making a Making a statement on the results of the experiment on whether the conclusion hypothesis made is accepted or rejected. Communicating in detail on all aspects of the experiment so that the Preparing a outcome of the experiment can be shared for the development of report chemistry knowledge. Figure 1.6 Steps in a scientific method 9 THEME 1 The Importance of Chemistry Based on the scientific method that you have learned, carry out Experiment 1.1 to study the effect of temperature on the solubility of salt in water. Experiment 1.1 Aim: To study the effect of temperature on the solubility of salt in water. Problem statement: Does the temperature of water affect the solubility of salt in water? Hypothesis: The increase in temperature of water will increase the solubility of salt in water. Variables: (a) Manipulated : Temperature of water (b) Responding : Solubility of salt in water (c) Fixed : Volume of water, mass of salt, time Brain Teaser Materials: Distilled water and salt Apparatus: 150 cm3 beaker, 100 cm3 measuring cylinder, thermometer, electronic scale, glass rod, Bunsen burner, stopwatch, wire gauze and tripod stand Procedure: Brain Teaser 1. Measure 50 cm3 of distilled water at temperature 10 °C How can you obtain with a measuring cylinder and pour it into a beaker. distilled water at 10 °C? 2. Add 40 g of salt into the beaker and stir the solution with a glass rod for 2 minutes. 3. Observe the solubility of salt in the beaker. 110 100 4. Repeat steps 1 to 3 with distilled water heated at 90 Glass rod 80 Thermometer 70 30 °C and 80 °C. 60 50 40 5. Record your observations in Table 1.1. 30 20 10 Distilled water 0 –10 Results: Salt Table 1.1 Temperature (oC) 10 30 80 Bunsen burner Observation Interpreting data: Figure 1.7 At which temperature does all the salt dissolve in water? Conclusion: Is the hypothesis acceptable? What is the conclusion of this experiment? Prepare a complete report after carrying out this experiment. 10  Introduction to Chemistry CHAPTER 1 TestYourself 1.2 1. What is meant by scientific method? 2. Why is a scientific method important in chemistry? State your opinion. 3. You are given a bucket of ice cubes, a little sugar, a measuring cylinder and a stopwatch. Plan an experiment to determine whether sugar increases the melting rate of the ice. g 1.3 Usage, Management and Learnin tandard Handling of Apparatus and S Materials At the end of the lesson, pupils are able to: The laboratory is an important place for learning chemistry, and 1.3.1 Explain the types and functions of self it is a dangerous place too. All the rules and safety measures in the protective equipments laboratory should be obeyed. Do you still remember the rules and and safety in the safety measures you have learned in Form 1? Figure 1.8 shows a laboratory poster of general rules in the laboratory. 1.3.2 Demonstrate methods of managing and handling apparatus and materials 1.3.3 Communicate about emergency management procedure in laboratory Chemistry CSDS (Chemical Safety Data Sheet) is a data sheet that gives information about chemicals to assist consumers in managing the risks of using dangerous chemicals. This data sheet contains complete information on chemical poisoning besides providing information on management and storage methods, and handling methods during an emergency. Figure 1.8 A poster of general rules in the laboratory (Source: National Institute of Occupational Safety and Health (NIOSH), Malaysia) 11 THEME 1 The Importance of Chemistry Personal Protective Equipment Wearing personal protective equipment while carrying out experiments in the laboratory is necessary to protect yourself from accidents. Figure 1.9 shows personal protective equipment in the laboratory and their functions. Other than the personal protective equipment, the chemistry laboratory is also equipped with various safety equipment. Figure 1.10 shows the safety equipment in the laboratory and their functions. Safety goggles Used for preventing dust or splashes of chemicals from getting into the eyes. Face mask Used for protecting the respiratory organs from chemicals in the form of powder or fumes. Gloves Used for handling chemicals to protect hands from injuries, chemicals or infections. Laboratory coat Used as protection for the body and clothing against chemical spills such as acids, alkalis and organic solvents. Laboratory shoes Used for protecting the feet from injuries caused by chemical spills, sharp objects or toxic substances. Figure 1.9 Personal protective equipment in the laboratory and their functions 12  Introduction to Chemistry CHAPTER 1 Safety shower Is used to wash and clean the body when a chemical accident occurs on parts of the body. This equipment is also used to extinguish fire on clothings. Fume chamber Eyewash A specially designed equipment to Used for washing and cleaning carry out experiments that release the eye when accidents occur toxic vapours, cause combustions or on parts of the eye. produce pungent smells. Fire extinguisher Hand wash Used for removing chemical Used for extinguishing fire in substances, oil, dirt and the laboratory. microorganisms from the hands. Figure 1.10 Safety equipment in the laboratory and their functions Chemistry Examples of substances that release toxic vapour, cause combustion or produce pungent smell: Concentrated sulphuric acid Chlorine gas Ammonia gas Bromine gas Alcohol Benzene 13 THEME 1 The Importance of Chemistry Methods of Managing and Handling Apparatus and Chemicals Skills in using and handling apparatus and materials are important and very useful in carrying out a scientific investigation. Carry out Activity 1.5 to find out the correct methods of managing and handling apparatus. Activity 1.5 Using and handling apparatus correctly 1. Carry out this activity in groups. 2. Each group should take turns in carrying out the four activities according to the stations by using and handling apparatus and chemicals with the correct methods. Visit the website or scan the QR code for each station. (a) Station 1 - Weighing and heating of solid (c) Station 3 - Electrolysis, gas collection and gas test Station 1 Station 3 http://bit.ly/ http://bit.ly/ 2MzE6Do 2MzEMbU (b) Station 2 - Filtration and distillation (d) Station 4 - Titration Station 2 Station 4 http://bit.ly/ http://bit.ly/ 2pI0scC 2W3RLpl Storage and Disposal of Chemicals How can the What do you understand about the storage and disposal chemicals in the Different types of of chemicals based on the conversation in Figure 1.11? laboratory be stored chemicals should Most chemicals in the laboratory are hazardous. or disposed of? be stored and disposed of using Chemicals should be stored properly so that they do different methods. not endanger the user nor cause accidents. Therefore, chemicals should be stored in their designated places according to their categories.    Disposal of chemicals is equally important as the storage of chemicals. Disposal of chemicals without following the correct disposal procedures not only causes environmental pollution but also destroys the habitats of flora and fauna and endangers human health as well. Hence, the storage and disposal of chemicals should be taken seriously by all parties. Figure 1.11 Storage and disposal of chemicals 14  Introduction to Chemistry CHAPTER 1 Storage of Chemicals Chemicals have specific storage methods according to the types of substances. Look at the following examples: Reactive substances Reactive metals such as lithium, sodium and potassium are stored in paraffin oil to prevent reaction with the moisture in the air. Hydrocarbons and organic solvents Photograph 1.1 Sodium in paraffin oil Volatile and inflammable liquids like hydrocarbons and organic solvents should be stored in shady areas far from sunlight and heat source. Substances that decompose easily Substances that decompose easily in the presence of light, for example concentrated nitric acid, hydrogen peroxide solution, silver nitrate solution, liquid bromine and liquid chlorine are stored in dark bottles. Photograph 1.2 Hydrogen peroxide Substances with pH9 stored in a dark bottle Corrosive chemicals (pH9) are usually stored in special storage cabinets that are kept locked. Heavy metals and toxic substances Toxic substances and heavy metals should be kept in special labelled containers and kept in a locked room which is heat free. Guidelines on storage of Photograph 1.3 Cabinet for keeping hazardous substances corrosive chemicals http://bit.ly/2MfxBoT 15  Brain Teaser THEME 1 The Importance of Chemistry Disposal of Chemicals Brain Teaser Can all the chemical Laboratory wastes have specific disposal methods wastes in the laboratory be according to the types of substances. disposed of into the sink or dustbin? Justify. Hydrogen peroxide Hydrogen peroxide wastes with a low concentration can be poured directly into the laboratory’s sink. However, hydrogen peroxide with a high concentration has to be diluted with water and added with sodium sulphite for the decomposition process to take place before being poured into the sink. Solid wastes Solid wastes like glass and rubber have to be disposed into special containers. Organic solvents and hydrocarbons Most organic solvents and hydrocarbons are toxic, carcinogenic, volatile and inflammable. This type of wastes cannot be disposed directly into the sink or the laboratory drain because it would pollute the water source and the environment. Organic solvent and hydrocarbon wastes should be kept in special containers made of glass or plastic. Photograph 1.4 Substances with pH9 A closed container for disposing hazardous wastes Substances with a pH value of pH9 are strong acids and strong alkalis respectively. Strong acid and alkali wastes can cause damage to the sink and react with water to release high heat and toxic gases. Strong acid and alkali wastes should be Chemistry kept in closed labelled containers during disposal. According to Malaysian regulations, chemicals Heavy metals and toxic substances that are classified as listed Solutions containing heavy metals and toxic substances have to wastes should be disposed be kept in plastic bags and the solutions be left to evaporate in according to standard procedures. The guidelines the fume chamber. Then, the bag of heavy metal residue is tied for listed wastes can carefully and is put into the container of heavy metal waste. This be obtained from the type of substances should be discarded and disposed according Department of Environment to standard procedures. of Malaysia. Volatile substances Substances such as alcohol, ammonia and bromine are volatile, that is easily converted to gas at room temperature. Some of the gases produced from volatile substances are hazardous to humans and can be fatal if inhaled in large amounts. Volatile wastes should be stored in closed containers and kept away from sun and heat. 16  Introduction to Chemistry CHAPTER 1 Chemical wastes and apparatus contaminated by chemicals should be disposed of into bins or bottles labelled with the types of wastes. Then, the waste will be sent to disposal centres. Photograph 1.5 Bin and bottle for chemical waste disposal Emergency Management Procedure in the Laboratory Waste spills continue to occur in laboratories even with safety measures in place. When these accidents happen, you should act according to the correct procedure as shown below: 1 Inform your teacher or the laboratory assistant about the accident immediately. 2 Prohibit other students from entering the accident site. 3 Stop the spill from spreading to other areas by using sand to border it. 4 Clean the chemical spill. 5 Dispose of the chemical spill by following the correct procedures. Mercury thermometers are often used to carry out experiments News on mercury in the school laboratory. If the mercury thermometer breaks, a pupil spill faces the risk of mercury spill. Although the quantity of mercury http://bit.ly/ in the thermometer is very minimal, it is enough to cause mercury 2MxQZh9 poisoning. Mercury poisoning occurs when a person is exposed to mercury in certain amount. Symptoms of mercury poisoning: Mercury is volatile at room Nausea temperature. Mercury vapour Coughing poisons the air. Vomiting Diarrhoea Do not touch mercury Chest pain spill because it can Sore throat absorb into your body Difficulty in breathing through the skin. Headache Eye irritation Vision problem Increase in blood pressure Figure 1.12 Mercury spill 17 THEME 1 The Importance of Chemistry Steps to be taken the moment mercury spill occurs. 1 Inform your teacher or the laboratory assistant about the accident. 2 Make the spill site as the prohibited area. 3 Sprinkle sulphur powder to cover up the spill. 4 Contact the Fire and Rescue Department for further action. If you are exposed to mercury poisoning, you should: Guidelines on handling Stay away from the mercury source to prevent mercury spill further exposure to it Go to the hospital for treatment http://bit.ly/ 2MJRqng Activity 1.6 Century Discussing the emergency management procedures in the laboratory 21st Skills 1. Carry out the Gallery Walk activity. 2. Surf the Internet to gather information on the types of accidents that commonly occur in the laboratory and emergency management procedures. 3. Prepare a presentation of your information. 4. Display the information in the class. 5. Each group should move to observe the information of the other groups. Write comments on the other groups’ information on sticky notes and paste them. TestYourself 1.3 1. List out three safety steps while in the laboratory. 2. Give the functions of the following equipment: (a) Fume chamber (b) Safety shower (c) Laboratory coat 3. How would you manage solid wastes such as glass and rubber in the laboratory? 4. Explain how you would test the presence of oxygen and hydrogen gases. 5. Explain how you can get the most accurate reading in titration. 18  Concept Study of: Structure of matter Systematic method to Personal protective equipment Properties of matter solve scientific problems Composition of matter Interaction between matter meaning safety in the Safety equipment Scientific meaning laboratory method method steps accidents Chemical spill of study Chemistry Making observations Mercury spill Making an inference management Identifying the problem importance and handling of Making a hypothesis Materials Identifying the variables Daily life Apparatus types Controlling the variables Planning an experiment Careers Collecting data methods Solid waste used in Interpreting data Substances with pH9 field of Distillation Organic solvents Writing a report Titration Cosmetics Medicine Hydrocarbons Filtration Hydrogen peroxide Pharmaceutical Agriculture Gas collection Toxic substances Quick Gas test Heavy metals Biotechnology Industries Volatile substances Electrolysis http://bit.ly/ Nanotechnology Heating of solids Reactive substances Introduction to Chemistry 33V9v9c Weighing of solids 19 Green technology CHAPTER 1 THEME 1 The Importance of Chemistry Self Reflection 1. What new knowledge have you learned in Introduction to Chemistry? 2. Which is the most interesting subtopic in Introduction to Chemistry? Why? 3. Why is the learning of Introduction to Chemistry important in the next chemistry lesson? 4. Rate your performance in Introduction to Chemistry on a scale of 1 to 10; 1 being the lowest and 10 the highest. Why would you rate yourself at that level? 5.  What else would you like to know about Introduction to Chemistry? http://bit.ly/ 2MEAuyw Achievement 1 1. Chemicals are substances that cannot be ignored in our daily lives. (a) State five types of chemicals that are commonly used in daily life. (b) For each chemical stated in (a), state its use. 2. (a) Name three industries in Malaysia that use knowledge of chemistry. (b) How do the industries stated in (a) benefit our country? 3. List out three types of personal protective equipment and state the function of each equipment. 4. Complete the following flow chart on the steps involved in a scientific method. Making Making an Identifying the observation inference problem Writing a report 5. S tate the safety measures that should be taken to overcome mercury spill accidents that occur in the school laboratory. 20  Introduction to Chemistry CHAPTER 1 6. Three pieces of cloth with a size of 10 cm × 10 cm each are sprinkled with 20 cm3 of distilled water. Then, all the three pieces of cloth are folded in different styles and left to dry at room temperature. The time taken for each piece to dry is recorded. (a) Explain why the three pieces of cloth are folded in different styles. (b) Suggest a hypothesis for this experiment. (c) Make an inference for this experiment. (d) Determine the variables involved in this experiment. (e) Construct a suitable table to record the readings in this experiment. Enrichmen Corner 1. Figure 1 shows several examples of waste substances in the school laboratory. Broken Ethanol Concentrated Dilute conical flask acid NaOH Used gloves Used litmus paper Bromine Figure 1 (a) Based on Figure 1, list out wastes that cannot be disposed of into the school sink or the rubbish bin. (b) Explain how to manage the waste substances listed in (a) correctly. 2. H  alim is a farmer. He plants various types of vegetables to supply the local market. However, lately, Halim realised that the produce was unsatisfactory and the growth of vegetables was stunted, or the vegetables had died off. He suspected the soil to be acidic. As a scientist, you are asked to help Halim to determine the most suitable pH value of the soil for planting vegetables. Suggest a suitable hypothesis and state briefly how you can control the variables in this experiment. STEM Check Answers http://bit.ly/ 3442zGX 21