Welcome to Chemistry 116! Lab Safety and Proper Procedure Labs 1 & 2

How to print out notes Go to file, click on print, look for print what change from slides to handouts; then adjust how many you want per page. Also change color to pure black & white.

Introduction Today, we will look at some common chemistry lab equipment and its proper use. The equipment you will be using: beakers graduated cylinders burettes Eudiometer tubes Balance Bunsen Burner

The Beaker & the Graduated Cylinder The graduated cylinder allows you to deliver precise volumes of liquid. The beaker is useful for transferring solutions from one vessel to another.

Procedures Page Bunsen burner Demo: learn the proper use 2. Measuring length: measure the length of a test tube  0.1 cm 3. Using a top-loading digital balance measure the mass of one 100 beaker on both the centigram and the milligram balance 4. Omit 5,6,7 analytical balance procedure, reading volume measurements using the meniscus, and determine accuracy in measuring liquid volumes

The Digital Balance The top loading balance in a general lab will be accurate to: 0.01 grams - centigram balance grams - milligram balance or grams is considered analytical.

Bunsen burner

Step 1 Shut the air control.

Step 2 Shut the gas control valve, and then open it a small amount.

Step 3 Put safety goggles on!

Step 4 Open the wall valve ½ way.

Step 5 Carefully light the burner. Always use the striker at a 45 degree angle

Step 6 The initial flame is low on oxygen and not very hot. When the hole is closed and air is excluded from mixing with the jet of gas, a yellow, luminous flame is produced

Step 7 Open the air control until the central blue cone forms.

Step 8 The hottest part of the flame is just above the central blue cone. (There is no combustion inside the central cone.)

Step 9 Be sure to close the wall valve when done.

Density Density is the amount of mass per given volume: It is specific to every substance It is often referred to as specific gravity m is expressed in grams and v in milliliters ex: Water is 1g/mL

Lab# 2 pg35-37 Pg 35 Determine the density of various samples of water. –Obtain and determine the mass a empty 100mL. beaker. –Record the mass of the empty beaker. –Add 5mL. of water to the beaker and determine the mass. –Add 5mL. More of water and determine the mass. – Repeat process until a total of 25mL. of water has been added to the beaker.

Lab # 2 Continued Pg36 # 2 Determine the density of aluminum by displacement. –Obtain a sphere, slide it into graduated cylinder to determine the volume of the sphere. –Calculate density # 3 Determine the density by direct measurement. – Obtain a cube and measure LxWxH to determine volume –Calculate density.

% error

Due Next Week Pre-lab # 1 pg11 Pre-lab # 5 pg 41 Pg 23 questions 1-4 omit #5 -7 Pgs 35 Graph of Volume Vs. Mass data from table # 1 pg 36 Part A Density of aluminum by displacement Pg 36 Part B Density of aluminum by direct measurement Pg 37 questions