LAB MODULE 1

• Common Laboratory Apparatus:
• Graduated cylinder:

  • Also known as measuring cylinder
  • Used to measure a precise volume of a liquid
  • Features a narrow cylindrical shape with markings along the cylinder that represent the amount of liquid being measured
• Dessicator:

  • Used to store dried samples in a dry atmosphere
  • Should not be used to dry an object, but to maintain an already dried object indefinitely in a dry condition
• Syringes:

  • Used to precisely measure liquids and are calibrated in milliliters (mL)
• Pipet:

  • Measuring instrument consisting of a graduated glass tube used to measure or transfer precise volumes of a liquid by drawing the liquid up into the tube
• Buret:

  • Used to deliver solution in precisely-measured, variable volumes
  • Used primarily for titration, to deliver one reactant until the precise end point of the reaction is reached
• Volumetric flask:

  • Used to prepare solutions to an accurate volume
  • Has a calibration line engraved on the narrow part of its neck
  • The calibration line is specific to a given flask
• Erlenmayer flask:

  • Used to hold and mix chemicals
  • The small neck is to facilitate mixing without spilling
• Analytical balance:

  • Highly sensitive lab instruments designed to accurately measure mass
  • Readability range between 0.1mg - 0.01mg
• Laboratory thermometer:

  • Used to measure temperature in Celsius
• Centrifuge:

  • Laboratory device used for the separation of fluids, gas or liquid, based on density
  • Separation is achieved by spinning a vessel containing material at high speed; the centrifugal force pushes heavier materials to the outside of the vessel
• Crucible and cover:

  • Used for holding chemicals during heating to very high temperatures
• Crucible tong:

  • Used to hold crucibles
• Test tubes:

  • Used to hold and mix liquids
• Beaker:

  • Used to hold, mix, and heat liquids
• Hot plate:

  • Generally used to heat glassware or its contents
• Single-Pan Balance (Single-Pan Mechanical Analytical Balance):

  • Appeared on the market in 1946
  • The speed and convenience of weighing with this balance were vastly superior to what could be realized with the traditional equal-arm balance
  • This balance rapidly replaced the latter in most laboratories
  • Currently being replaced by the electronic analytical balance
• Weighing Bottles:

  • Laboratory equipment used for precise weighing of solids
  • Thin-walled glass container, with a ground-glass stopper, used for weighing samples of chemical substances
• Filter Paper:

  • Semi-permeable paper barrier placed perpendicular to a liquid or air flow
  • Used to separate fine solid particles from liquids or gases
• Evaporating Dish:

  • Used to heat liquids for evaporation
• Petri Dish:

  • Shallow cylindrical containers with fitted lids designed specifically for microbiology or cell culture use
• Process of cleaning the laboratory apparatuses:

  • Every beaker, flask, or crucible that will contain the sample must be thoroughly cleaned before being used
  • The apparatus should be washed with a hot detergent solution and then rinsed—initially with large amounts of tap water and finally with several small portions of deionized water
• Drying the interior surface of glassware before use:

  • It is seldom necessary to dry the interior surface of glassware before use
  • Drying is usually a waste of time and is always a potential source of contamination
• Chemical substances that can be used in removing grease films in laboratory apparatuses:

  • An organic solvent, such as methyl ethyl ketone or acetone, may be effective in removing grease films
• Importance of marking the laboratory ware during an experiment:

  • A chemical analysis is usually performed in duplicate or triplicate
  • Each vessel that holds a sample must be marked so that its contents can be positively identified
  • Flasks, beakers, and some crucibles have small etched areas on which semipermanent markings can be made with a pencil