Lab Practical 1 (Units 1-6) Flashcards
Describe the base units of the metric system
Meter
Liter
Gram
Explain what metric unit is used to measure volume, length, mass, and temperature
Meter= length/distance Liter= volume Gram= mass Temperature= celsius
Know how to convert between metric units with the same base (move the decimal)
0.013 deciliters= 1,300,000 nanoliters
480,000 micrometers= .048 decameters
Know the metric prefixes, their abbreviations, and how much of the base unit they represent
T-Tera- 10^12 G- Giga- 10^9 M- Mega- 10^6 k- Kilo- 10^3 h- hecto- 10^2 da- Deka- 10^1 meters, liters, grams- 10^0 d- deci- 10^-1 c- centi- 10^-2 m- milli- 10^-3 u(kindof)- micro- 10^-6 n- nano- 10^-9 p- pico- 10^-12
Convert between different metric base units (1g=1ml=1cc) of water at standard conditions
freezing: 0 C = 32 F
Room Temperature: 21.1 C = 70 F
Body Temperature: 37 C = 98.6 F
Boiling: 100 C = 212 F
1 cc = 1 ml
1 ml = 1 g
1 liter = 1 kg
1 dm^3 = 1 liter
50 ml of water weighs 50 g
3 liters of water equals 3 kg
1 liter = 1000 ml
Describe how to convert from Fahrenheit to Celsius and how to convert from celsius to Fahrenheit
F to C
- F-32
- Multiply by 5
- Divide by 9
C to F
- C x 9
- Divide by 5
- Add 32
Identify all lab equipment used in unit 1
Graduated Cylinder Beaker Erlenmeyer Flask Triple Beam Balance Digital Balance/Scale Graduated Pipette (Pipette) Weigh Boat Hot/Stir Plate Stir Bar Pipette Pump Beaker Tongs Test Tube Tongs
Draw/define meniscus
When measuring the volume of a liquid in a graduated cylinder, you will observe a “meniscus.”
The meniscus is the curved upper surface of a liquid in a tube. You measure the liquid/volume from the bottom of the curve
(which is in the middle) of the meniscus.
Know which lab items are most accurate when measuring volume (2)
Graduated Cylinder
glass pipette
Know how to appropriately measure the mass using both the electronic balance and the triple beam balance
Digital/Electronic Balance/Scale
- Locate and place the weigh boat on the digital balance.
- “Tare” the digital balance in order to reset the balance to “0” grams. This will ensure that you do not add the weight of the weigh boat to what you are weighing.
Triple Beam Balance
- On the triple beam balance, you set the item on the metal pan without the weigh boat.
- Make sure it is set to zero by using the adjustment knob underneath the pan.
Understand if something should be measured in grams or kg
Grams are smaller than kilograms, so something smaller would be measured in grams.??
Know how to appropriately measure length using rules and meter sticks
Something smaller would use a ruler to find the length.??
Predict if an item would be appropriately measured in mm, cm, m, or km
Depends on the size of the item??
Distinguish between weight and mass
Mass is a measure of how much matter an object has.
Weight is a measure of how strongly gravity pulls on that matter.
Write numbers in scientific notation
0.000554433= 5.54433 x 10^-4 457430= 4.57430 x 10^5
Take a number in scientific notation and write in long form
- 11 x 10^-4= 0.000911
8. 992233 x 10^6= 8992233
Calculate the mean, median, and range of a set of numbers
Mean: an average of a group of measurements
add all values and divide by total number of values.
Median: the value that is in the middle of a group of measurements.
Arrange values in order from lowest to highest. Then pick the middle one.
If there are an even number of values, pick the two middle and add them together then divide that by 2.
Range: the difference between the smallest and the largest measurements.
Subtract the smallest value from the largest value.
Known the definition of deviation, variance, and standard deviation
Deviation: Measures hoe the measurements vary from the mean (+ or -). In other words, what is the difference between an actual measurement and the mean, or average, of the sample?
Variance: This measures how much difference, or variation, there is between the values you have obtained. The smaller the variance, the closer the values will be to the mean. Likewise, the larger the variance, the farther the values will be from the mean.
Standard Deviation: Standard deviation gives you an idea of the widely spread your values are about the mean. The smaller the standard deviation, the closer your values will be to the average. If you were to graph data having a small standard deviation, you would expect a tall, thin bell shaped curve. On the other hand, if the standard deviation were large, your bell shaped curve would be wider.
(((LOOK AT THE UNIT 1 LAB MANUAL TO SEE HOW TO CALCULATE THESE THINGS)))
Describe why a pencil looks yellow
A pencil looks yellow because the white light is hitting it and all of the colors are being absorbed, but the yellow light is being transmitted back out, which is what makes the pencil appear yellow.
Correlate colors of visible spectrum with their corresponding wavelengths or range of wavelengths
Red= 620-750 nm Orange= 590-620 nm Yellow= 570-590 nm Green= 500-570 nm Blue= 450-500 nm Violet= 380-450 nm
Identify components of a spectrophotometer
Digital Display Mode Button Sample Holder Wavelength Knob 0% T Knob 100% T Knob
Know how to calibrate the spectrophotometer to 0% and 100% transmission
- Adjust the wavelength control knob until the digital display shows 540 nm. (Make sure the filter level is in the correct wavelength range.)
- Make sure that you use the zero control knob to set transmittance to “0” before inserting your blank tube. Insert the “blank” into the sample holder and close the lid.
- Adjust the meter reading 100% transmittance using the transmittance control knob.
What is the purpose of a blank tube?
A blank tube is a tube that is used in the spectrophotometry experiments that cancels out any unwanted molecules from absorbing light.
Describe the inverse relationship between transmittance and absorbance
As the amount of light transmitted by a solution increases, the amount
of light absorbed might be expected to decrease proportionally.
(((??the light absorbed by a solution depends on the absorbing ability of the
solute, the distance traveled by the light through the solution, and the concentration of the solution.??))
Transmittance measures how much light passes through the sample.
Absorbance measures how much light is absorbed by the substance.