AGBU Science Department Lab Manual

1. AGBU Science Department Lab Manual Units & Measures

2. AGBU Science Department Lab Manual Units & Measures A mole is equal to the gram molecular weight (or formula weight) of the solute. Molarity (M) equals the number of moles of solute in 1 liter of solution. A molar solution is one in which 1 liter of solution contains the number of grams equal to its molecular weight.  Example: Sodium Chloride (NaCl) has a formula (molecular) weight of 58.44 (22.990 for Na and 35.453 for Cl). To make up 1L of a 5M NaCl solution = 58.44 g/mol x 5 moles/liter x 1 liter = 292.2 g in 1 liter of solution. Molality (m) is equal to the number of moles of solute in 1000 g of solvent. For dilute solutions in water (a ml of water equals 1.0 g), there is little or no practical difference between a molar(M) solution and a molal(m) solution. In contrast, a 2 m sucrose solution (density of 1.18 g/ml) equals a 1.4 M sucrose solution.

3. AGBU Science Department Lab Manual FAHRENHEIT - CELSIUS CONVERSION Daniel Fahrenheit (1696 - 1736) - scientist from Amsterdam, established three fixed points on his thermometer: 0ºF - temperature of an ice, water, and salt mixture; second fixed point - 32ºF - temperature of the water-ice combination. His third fixed point was 96ºF as the temperature “when the thermometer is held in the mouth or under the armpit of a living man in good health”. After Fahrenheit died, scientists calibrated his model of thermometer using 212 degrees, the temperature at which water boils, as the upper fixed point. When the Fahrenheit thermometer was recalibrated, normal human body temperature registered 98.6 rather than 96. Post-Fahrenheit version of the Fahrenheit scale is now used in America, but most of the world prefers the scale named Celsius. The Celsius scale, devised by Swedish Astronomer Andres Celsius (1701-1744) for scientific purposes, has 100 degrees between the freezing point (0ºC) and boiling point (100ºC) of pure water at sea level air pressure. The term Celsius was adopted in 1948 by an International conference on weights and measures. The formulas needed to convert temperature from Fahrenheit scale temperature (commonly misspelled Fahrenheit) to Celsius scale: °C = (°F - 32) * 5/9 The formulas needed to convert temperature from Celsius to Fahrenheit: °F = °C * 9/5 + 32 CELSIUS - KELVIN CONVERSION °C + 273 = K

4. AGBU Science Department Lab Manual How to type a Lab Report Must be typed; Font size 12; Times New Roman, Arial; Color – black; Margins 1” or less. **It is OK to use first person in scientific writing, but it should be used sparingly – reserve the use of first person for things that you want to emphasize that “you” uniquely did (i.e. not things that many others have done as well). It is better to write in the third. For example: The experiment was completed; The solution was then mixed with the solid. Name Title Date of lab Partners: 1. 2. Abstract: Must consist of 5-10 sentences to form one paragraph. This is a brief summary of what the entire lab is 1-2 sentences of introduction of lab 1-2 sentences restating your hypothesis 1-2 sentences summarizing the procedure 1-2 sentences detailing the results 1-2 sentences of conclusion or explain the results Hypothesis: What do you think is going to happen and why. Rewrite hypothesis in past tense. Or Purpose: It there is no unknown and the experiment is a demonstration then a purpose may be substituted for the hypothesis. The Purpose of this exp. was to determine the color of light emitted from burning Mg ribbon. Procedure: Copy procedure from your lab Numbered In your own words and what you specifically did. Any differences or changes are included. In past tense The paper clip was bent and made a hook shape, and then it was pushed the long end through an index card. Repeated step 1. Enough solution was poured into the beaker to cover at least half of the paper clip. Data/observation: Draw data table (copying data table from lab paper or creating your own based on the info) Input all the info. Graphs, pictures, schematics can also be considered data Results: More detailed than the 1-2 sentences located in the abstract (should be at least a paragraph) Conclusion: 2-3 sentences that state and explain whether your hypothesis was correct or wrong (true or false) AND WHY!!! Ex. My hypothesis was proven to be true, because… What you may have done incorrectly. How you could expand on this lab. How this relates to everyday life outside of class… Answer any questions from the lab.