Lab Techniques Notes Name Chemistry Block #

I. Measuring Liquid Volume Measuring Instruments for Liquid Volume:

o Graduated cylindero Bureto Volumetric flask

Method:o Get at eye level with the measuring device o Measure at the bottom of the meniscus

Significant Figures:o Estimate one place beyond the markingso Every place must be marked to count towards sig figs

II. Measuring Temperature Method:

o Get at eye level with the measuring device o Measure at the bottom of the meniscus

Significant Figures:o Estimate one place beyond the markingso Thermometers frequently give halfway markings. These only help you

estimate that last digit. They do NOT give you another certain place.

III. Measuring Mass Method:

o Never place a chemical directly on the scale – use a secondary container like a weigh boat or a beaker

o Always make sure your scale is reading units of grams (g)o “Zero” or “Tare” resets the scale to 0.00 go If there is a cover on the scale, make sure it is closed when taring and

measuring as air currents can affect the measurement.o Never mass a hot object as it creates convective air currents inside the

balance chamber, altering the measurement. Significant Figures:

o Report all digits shown on the digital display

IV. Filtration Materials:

o Ring stando Iron ring

o Filter funnelo Filter paper (comes in circles of various

sizes)o Beaker or Erlenmeyer flask

Method:o Fold filter paper to make a cone to fit inside filter funnel

o Adjust iron ring to a height so that the tip of the funnel touches a side (for a beaker) and extends into the container

V. Paper Chromatography Materials:

o Chromatography (or filter) papero Solution for mobile phase (water or alcohol)o Pencil (or rod) and tape

Method:o Make a horizontal line across the strip in pencil about 2 cm from the bottom

Pencil does not move with the mobile phaseo Make a dot of sample on the penciled line o Tape the paper to a pencil so that it can be laid across a beakero Dip the bottom of the paper into the solution so that the pencil line is ABOVE the solution

You may need to roll the paper around the pencil to get it to the right height

VI. Heating a Test Tube Materials:

o Bunsen burnero Test tube o Test tube holder

Method:o Always hold test tubes in test tube holders when heatingo Point the opening of the test tube away from yourself and others in case of “bumping”o NEVER heat a closed test tube!o Heat the contents evenly by slowly waving the test tube back and forth through the flame.o Do not hold the test tube directly in the flame for extended periods of time.

VII. Lighting a Bunsen Burner Materials:

o Bunsen burnero Gas tubingo Match or striker

Parts of a Bunsen Burner:o Baseo Stalko Collar (adjusts air flow)o Pinwheel (adjusts gas flow)

Method:1. Turn the pinwheel and stalk until they are closed (righty tighty)2. Turn the pinwheel about 2 full turns open and the stalk about 3 full turns open (lefty loosey)3. Light a match4. Turn on the gas valve from the wall until parallel with the nozzle5. Bring the match up from below to light the gas flowing from the burner6. Adjust stalk (air flow) to get double blue cone in flame

7. Adjust pinwheel (gas flow) to change height8. Turn off burner from the gas valve on the wall (turn to fully perpendicular)