PRELIMS-IO-CHEM-LAB.docx

I. **GUIDELINES** 1. Secure the **borrowers slip** and fill it up properly. Be sure to **check all the items issued** for possible defects before leaving the counter. The laboratory experiment is conducted in groups. The group **leader** will be the one **responsible** in **borrowing...

I. **GUIDELINES** 1. Secure the **borrowers slip** and fill it up properly. Be sure to **check all the items issued** for possible defects before leaving the counter. The laboratory experiment is conducted in groups. The group **leader** will be the one **responsible** in **borrowing the needed materials** for that day experiment. 2. Carefully **follow the procedure** written in the manual. If you do not understand. 3. Before the end of each laboratory period, the group has to **submit their preliminary report** (that is the summary of the observations and results of the experiment) to the instructor for checking. **No experiment** shall be **considered performed** unless the **preliminary report** has been **duly checked** and **countersigned**. 4. Before leaving the laboratory, be sure to **return all borrowed items** **clean and dry** to the laboratory technicians/staff at the counter. 5. **Breakage** of apparatus, equipment, instruments and the like will be **charged to the offenders**, individually or collectively as the case maybe. Check all items before leaving the counter. - A **written record** of an investigation. Such a report is an **integral** of any laboratory experiment. The names and brief description of the sections of a laboratory report are here below: **PURPOSE** +-----------------------------------------------------------------------+ | II. **LABORATORY REPORT** | +-----------------------------------------------------------------------+ - A brief experiment of the **goals to be achieved** by conducting the experiment. This statement is always at the beginning of the experiment. **PROCEDURE** - In a laboratory manual, it is a **step-by-step activities** to be done in order to **gather information** needed to achieve the purpose of the experiment. **OBSERVATION AND DATA** - This section is a **running account** of what takes during the course of an investigation. **All** of your observations, **qualitative or quantitative** must **be recorded** in this section at the time the observation is made. Entries in the final two sections of the laboratory report will be pre-based on the information recorded here. Thus, it is vital that this information be **complete**, **well organized**, **accurate** and **properly labeled**. **CALCULATIONS** - In many cases the **raw data** collected during the course on an experiment must be "**processed**" before valid conclusions can be react. Processing data may include making **mathematical calculations** are then used as a **basis** on which to **draw conclusions**. **CONCLUSIONS AND QUESTIONS** - This section is where you **answer the question**. *Was the purpose of the experiment achieved?* In answering this question you must **provide evidence** to **support your answer**. +-----------------------------------------------------------------------+ | III. **SAFETY IN THE LABORATORY** | +-----------------------------------------------------------------------+ **OBJECTIVES:** 1. To work safely in the lab. 2. To identify common laboratory apparatus and their uses. 3. To become familiar with the laboratory rules and regulations, and to mark the safety features of the laboratory. **SAFETY RULES** 1. **Be prepared to work** when you **arrive** at the laboratory. If instructed to do so, **familiarize with the laboratory procedures** before the start of the experiment. 2. **Perform** **only** those **laboratory activities assigned** by your professor. 3. **Work areas** should always kept **clean and tidy**. Only **laboratory manuals** and **notebooks** should be brought to the work areas. 4. **Clothing** should be **appropriate** for working in the laboratory. Jackets, ties, and other **loose garment** should be **removed**. **Long sleeves** should be **rolled up** or secured in some manner. 5. **Long hair** should be **tied back** or **covered**, especially in the **vicinity of open flame**. 6. **Jewelry** that might **present hazard**, such as dangling necklace, chains, medallions, or bracelets **should *not* be worn** in the laboratory. 7. Carefully **follow all instructions**, both **written and oral**. 8. **Laboratory gowns** should always be **worn**. 9. **Set up apparatus** as **described** in the **laboratory manual** or as instructed by your **professor**. **NEVER USE MAKESHIFT ARRANGEMENTS**. 10. **Note** any **"caution" labels** before beginning an experiment. 11. **Keep** all **combustible materials away** from **open flames**. 12. **Never touch or taste any substance** in the laboratory **unless specifically instructed to do so** by your professor. 13. **Never put your face near the mouth of a container** that is holding the chemicals. 14. When **testing for odors**, use a **wafting motion** to direct the odor to your nose. 15. **Dispose waste materials** as instructed by your professor. 16. **Clean up all spills** immediately. 17. **Clean and wipe dry all work surfaces** at the end of the experiment. **Wash your hands** thoroughly. 18. **Know the location** and **how to use** the following: **first aid kit**, **fire extinguisher**, **emergency shower**, **emergency exit**. 19. **Report all accident** to your professor **immediately**. **HANDLING CHEMICALS** 1. **Read and double check labels** on reagent bottles **before usage**. **Take only** as much reagent as **you need**. 2. **Do *not* return unused reagent** to stock bottles. 3. When mixing acid and water, always **ADD ACID** to **WATER**. 4. **Avoid touching chemicals with your hands**, if chemicals do come contact with your hands, **wash them immediately**. **HEATING SUBSTANCES** 1. Exercise **extreme caution** when **using** a **gas burner**. Keep your **hand and clothing *away*** from the **flame**. 2. Always **turn the burner OFF** when **NOT in use**. 3. **Do not bring any substance into contact with the flame** unless instructed to do so. +-----------------------------------------------------------------------+ | IV. **COMMON LABORATORY APPARATUS** | +-----------------------------------------------------------------------+ **[Beaker]** - Serves as a **container** for substances. **[Erlenmeyer Flask]** - **Mixing chemical**s without using a stirring glass. (Swirling Method) **[Graduated Cylinder]** - **Accurate measurement** of chemical in bigger amount. **[Volumetric Flask]** - **Transferring and measuring accurate** volumes of liquid materials. **[Pipette/Pipet]** - **Transferring and accurate measurement** of **small amounts** of liquids. **[Aspirator]** - Used to **transfer chemicals** out of containers. **Accurate measurement** for **small amounts**. ***Note:** Press aspirator then contact mouth of pipette then use index finger to stop the liquid.* **[Evaporating Dish]** - **Container** of liquids that requires **evaporation**. **[Watch Glass]** - **Cover for beaker** or a surface (**container**) to evaporate liquids, hold solids while being weighted, heating a small amount of substance. **Concave glass**. **[Mortar and Pestle]** - To **grind** solids to powder. **Mortar = container**, **Pestle = grinder**. **[Glass Funnel]** - A **guide** for liquids or powder into **small openings**. - Used to **collect** solid substances. **[Stirring Rod]** - Used for **mixing** liquids in **beaker**. **[Alcohol Lamp]** - Used for **heating**, **sterilization**, and **combustion**. **[Bunsen Burner]** - Used for **heating**, **sterilization**, and **combustion**. **[Tripod]** - Provide **stable platform** for heating and mixing experiments. **[Wire Gauze]** - Provide **stable, heat resistant surface** for containers and helps **distribute heat evenly**. **[Clay Triangle]** - Used to **support crucible** when **heated**. **[Fish Tail]** - Placed to **burner** for **uniform heat** or flame. **[Test Tube]** - Used to **mix chemicals**, **hold liquids**, **heat** liquids, **grow bacteria**, and **collect** or **store bodily fluids**. To test different substances. **[Test Tube Rack]** - Used to **hold multiple test tubes** at the same time. **[Test Tube Brush]** - Used for **cleaning test tubes** and **narrow laboratory glasswares**. **[Crucible and Cover]** - Used to **expose substances** to **extreme heat**. - Used to **hold heated crucible**. **[Filter Paper ]** - Used to **filter liquids** from solids together with glass funnel. **[Nichrome Wire (inorg/org chem) /Inoculating Loop (bacte)]** - Used to check the color of the flame (**flame test**). **[Funnel Stand]** - Used to **support** and **hold funnel** in place. **[Iron Stand]** - Used to hold other kinds of equipment and glassware. **[Burette]** - To **dispense small volumes of liquids** (aliquots), or sometimes **gas** with **high accuracy**. **[Thistle Tube]** - Used to **add small volumes** of **liquid**. **[Waste Bottle]** - **Dispose used chemicals.** ***[LESSON 2]*: MEASUREMENT** **MASS** **Total Mass** Add all the mass of the items **Mass 1 + Mass 2 + Mass 3 + Mass 4...** = Total Mass ---------------------- ---------------------------------------- ------------------------------------------------------- **Average Mass** Divide total mass over number of items **Total Mass ÷ \# of items** = Average Mass **Mass of Two Sets** Add the two sets **Set 1 + Set 2** = Total Mass of 2 sets **DEVIATION** +-----------------------+-----------------------+-----------------------+ | **Deviation** | Subtract mass per | **Average mass - Mass | | | coin sa average mass | per coin** = | | | | Deviation | +=======================+=======================+=======================+ | **Average Deviation** | Add all deviation | **Total deviation ÷ | | | then divide to the | \# of items** = | | | number of items | Average Deviation | +-----------------------+-----------------------+-----------------------+ | **Average Mass of | Average deviation | **Average deviation ÷ | | Deviation** | divide to the number | \# of items** = | | | of items | Average Mass | | | | Deviation | +-----------------------+-----------------------+-----------------------+ | **Symbols** | Solid | **g/cm** | | | | | | | Liquid/Gas | **g/ml, g/li** | +-----------------------+-----------------------+-----------------------+ **CIRCLE FORMULA** **Diameter (cm)** r² ------------------- -------------- **Radius** Diameter ÷ 2 **DENSITY BY GEOMETRIC MEASUREMENT** **Geometrical Volume** Π x r² x h ------------------------ ------------------ **Density** Mass ÷ Volume **Mass** Density x Volume **Volume (ml)** Mass ÷ Density **DENSITY OF LIQUIDS** **Volume (ml)** Final volume -- initial volume -------------------------- ------------------------------------------------------------------ **Percentage Error (%)**  **Water** 1 gram (theoretical value) **Ethanol** 0.79 gram (theoretical value) **Coconut oil** 0.92 gram (theoretical value) **TEMPERATURE** **Farenheit to Kelvin** (F-32) x 5/9 + 273 ------------------------- -------------------- **Celsius to Kelvin** Deg C + 273 **Kelvin to Celcius** K - 273 **Kelvin to Farenheit** (K-273) x 1.8 + 32  ***[LESSON 3:]*** **HEATING IN THE LABORATORY** +-----------------------------------------------------------------------+ | I. **IMPORTANCE OF HEATING** | +-----------------------------------------------------------------------+ 1. It can be used to **cause physical** or **chemical changes**. 2. It can be used to **speed up a change**. +-----------------------------------------------------------------------+ | II. **3 TYPES OF GAS BURNERS** | +-----------------------------------------------------------------------+ **Bunsen Burner** What are Bunsen burners? **PARTS** **FUNCTION** ------------------------------------------------------- ------------------------------------------------------ **Mouth** Where the **flame appears**. **Barrel** (also called Tube, Burner Tube, Body Tube) Where the **air and gas mix**. **Collar** (also called Air Regulator) **Regulates the amount of air** entering the burner. **Air Hole** (also called Air Inlet) **Entrance** of the **air**. **Stopcock** **Replacement to gas regulator.** **Rubber Hose** (also called Rubber Tube, Gas Hose) **Gas source**. **Gas inlet** **Base** **Supports** the whole burner. **Tirril Burner**  **Meker Burner** Meker burner with grid and tap **Differences of the Burners** +-----------------------------------+-----------------------------------+ | **Meker** | **Bunsen and Tirril** | | | | | - Its **nozzle** has **mesh** | - Has **fish tail** that | | that distributes **even | distributes **even flame**. | | flame**. | | +===================================+===================================+ | **Tirril and Meker** | **Bunsen** | | | | | - Has **gas regulator**. | - Has **gas valve**. | +-----------------------------------+-----------------------------------+ +-----------------------------------------------------------------------+ | III. **LIGHTING THE BURNER** | +-----------------------------------------------------------------------+ Examine your burner. It consists of **three parts**: a **gas inlet** with a **gas control valve** in the base; an **air inlet control sleeves**; a **barrel** in which the **gas and air mix** before the ignite at the top of the barrel. **PROCEDURE:** 1. Before attempting to light the burner, check that the **air inlet is almost completely close** and the **gas inlet is closed**. 2. **Open** the **gas inlet partially**. 3. With the **burner lighter** held **over the top of the barrel**, **turn on** the **gas supply valve fully** and **strike the lighter repeatedly** until the **gas ignites**. 4. If it **does not ignite** within **half a minute**, **turn off** the **gas supply valve** to present build-up of gas in the laboratory. 5. **Wait one minute** and then **open the gas supply valve again** and **re-attempt to relight**. 6. If still unsuccessful, ask for assistance. +-----------------------------------------------------------------------+ | IV. **YELLOW AND BLUE FLAME** | +-----------------------------------------------------------------------+ 7. After the experiment, **close the air inlet** on the burner, then the **gas inlet** and finally the **gas-supply valve**. The **flame** should be **yellow-tipped** and about **6 cm**. **Open the air inlet sleeves** until there is no traces of yellow in the flame. **Sharp blue cone** Correctly-adjusted flame ---------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------ **Flickering yellow flame** Increase air flow **Flame lifting off** Decrease air flow **Flashback** (fire inside the burner because of too much air) *Turn off* the burner immediately at the *gas-supply valve* and *relight* after *reducing the air supply*. **YELLOW FLAME** (insufficient air) - Luminous flame - Incomplete combustion - Lingering, insufficient - Produces black soot (carbon) **BLUE FLAME** (sufficient air) - Non-luminous flame - Complete combustion - Steady, sufficient - Can remove black soot - Has 2 parts: Inner and Outer Flame - Inner Flame: colder part (7 seconds) - Outer Flame: hottest part (3.67 seconds) ***[LESSON 4:]*** **PHYSICAL AND CHEMICAL CHANGES** +-----------------------------------------------------------------------+ | I. **MATTER** | +-----------------------------------------------------------------------+ - It undergoes 2 kinds of changes: **physical and chemical change**. - **Physical Change**: changes in size, shape, color, and physical state but no new substance is formed. - **Chemical Change**: the **original substances** are **transformed** into **new substances**. These new substances **differ** in **chemical properties and composition** from the original substance. +-----------------------------------------------------------------------+ | II. **ENERGY CHANGE** | +-----------------------------------------------------------------------+ - Transformation of matter is accompanied by **energy change**. - **Chemical Change**: **heat**, **light**, and **electrical energy**. - **Chemical reactions** are characterized by the **absorption** or the **emission of heat**. The burning of fuel is always accompanied by the **evolution of heat**. - **Physical Change**: may also be accompanied by **heat changes** when certain substances are **dissolved in water, heat** may be either **absorbed** or **given off.**