Glassware and Density PDF

SOME COMMON FIRST AIDS Injury: Cuts, bruises 1 2 3 Do not touch an Pressing directly Apply cold open wound on minor cuts compress to without safety will stop bleeding bruises to reduce gloves in a few minutes s...

SOME COMMON FIRST AIDS Injury: Cuts, bruises 1 2 3 Do not touch an Pressing directly Apply cold open wound on minor cuts compress to without safety will stop bleeding bruises to reduce gloves in a few minutes swelling If laboratory Alert the instructor immediately. glassware is Don't touch it broken  Provide fresh air and have the person recline so that their head Fainting is lower than the rest of their body.  Alert the instructor immediately. Injury: Poisoning Find out what substance caused the poisoning  Alert the instructor immediately. Injury: Shut down the current at the Electrical shock source Remove wire with rubber gloves.  Flush with large quantities of water. For acid spills: apply baking Spills on the skin soda solution. For base spills: apply vinegar or boric acid.  Flush eyes immediately with plenty of water for several minutes. Injury: Eyes If a foreign object is lodged in the eyes, do not allow the eyes to be rubbed. Commonly used glassware in a chemistry lab Pipettes A. Disposable transfer pipette These pipettes are made of plastic and are useful for transferring liquids drop wise.  Pipettes C. Graduated pipettes. D. Volumetric pipette. These pipettes possess These glass pipettes are used to markings that allow measured transfer liquids when quantities of liquids to be the quantity of liquid transferred. must be accurate. They are often used to These pipettes are transfer for example, volume of used to transfer one reagent or solvent for dilution. fixed volume such as 1 mL or 10 mL. PIPETTE PUMPS Graduated cylinders, beakers, and Erlenmeyer flasks  Graduated cylinders, beakers, and Erlenmeyer flasks A. Graduated cylinders B. Beakers C. Erlenmeyer flasks Used as containers. Available in a variety of sizes. Used as reaction vessels, particularly in Transfer liquids with They often possess volume titrations. a moderate degree of markings, but these are only rough accuracy. Volume markings estimates of the liquid volume. should not be The markings are not necessarily considered accurate. accurate. Volumetric flasks Used to measure and store solutions with a high degree of accuracy. These flasks generally possess a marking near the top that indicates the level at which the volume of the liquid is equal to the volume written on the outside of the flask. Burette Vertical cylindrical piece of laboratory glassware with a volumetric graduation on its full length and a precision tap, or stopcock, on the bottom. Used to dispense known amounts of a liquid reagent in experiments for which such precision is necessary, such as a titration experiment. Burettes measure from the top since they are used to measure liquids dispensed out from the bottom. The difference between starting and final volume is the amount dispensed Additional Equipment A. Bunsen burner. B. Funnel. C. Test tubes. D. Test tube rack. E. Test tube brush. F. Test tube holder G. Clamp and clamp extension. WEIGHING AND THE ELECTRONIC BALANCE  Weighing and the Electronic Balance Mass determination by weighing is a fundamental task that requires a balance. Balances are precision instruments , easy to use, and it takes seconds to weigh an object. All balances display an object’s mass directly on an LED display. Most common types of balances : 2 digit balance 4 digit balance Determination of density of some substances Determination of density of some substances Objective 1) To learn how to use some common laboratory devices. 2) To determine the density of water. 3) To identify a given unknown substance by comparing its density with reference values. Determination of density of some substances Density is the mass of substance per Mass Density = unit volume of the Volume substance. Unit of density is Kg/m3 or g/cm3 (g/mL).  Procedure: 1- Weigh accurately a small beaker (W1). 2- Put 10 ml of the liquid to be determined by volumetric pipette in the previously weighed beaker and get the new weight (W2). 3- Weight of liquid (W3) = W2-W1 Weight W3 Density = = Volume 10 (volume of liquid) 4- Repeat the above steps using the given unknown substance. Calculate the unknown’s density then predict its kind by comparing its density with those given in the following table. Data and observations Calculations Results