PSI Chemistry. Table spoons, disposable weighing dishes, scale, pencil and instruction hand out.

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Sara French
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1 Chemistry Honors Lab PSI Chemistry Names Measuring Mass As A Means Of Counting - Chemical quantities- Mole and Particles Purpose To determine the mass of given chemicals and use the data to count atoms. Materials: sodium chloride, calcium carbonate and water. Table spoons, disposable weighing dishes, scale, pencil and instruction hand out. Safety: Wear safety glass and lab apron. Procedure Record the mass of an empty weighing dish. Add 1 table spoon of sodium chloride and weigh again. Subtract the weight of the empty dish to get the mass of sodium chloride alone. Repeat with other chemicals. Record the measured and calculated data into the data table. Reproduce the following grid in a separate sheet of paper if necessary. Mass (grams) H2O (l) NaCl (s) CaCO3 (s) Molar Mass (g/mol) Moles of Compound Moles of Element Atoms of Element H= H= Na= Cl= Na= Cl= Ca= C= Ca= C= Prediction Predict which of the three compounds contains the most atoms. Circle the Choice.

2 NaCl H2O CaCO3 Analysis 1. Calculate the moles of water contained in one level teaspoon water and record the results in the table. Moles of H2O =? g H2O x 18 g 2. Repeat Step 1 for the remaining compounds. Use the periodic table if necessary to calculate the molar mass of sodium chloride and calcium carbonate. 3. Calculate the moles of each element present in the teaspoon sized sample of H2O. Moles of H =? mol H2O x Repeat for all of the other compounds in the table. 2 mol H 4. Calculate the number of atoms of each element present in the teaspoon-sized sample of H2O atoms of H =? mol H2O x 6.02x10 23 molecules of H2O x 2 Repeat for all of the other compounds in the table. 5. Which of the three teaspoon-sized samples contains the greatest number of moles? NaCl H2O CaCO3 6. Which of the three compounds contains the most atoms? NaCl H2O CaCO3

3 A different approach As a Discovery lab- Mole -particles In this laboratory investigation, you and your lab will design and execute an experiment to answer the following question. Which contains the greatest number of atoms: 1 teaspoon of sodium chloride (table salt), 1 teaspoon of water, 1 teaspoon of calcium carbonate (chalk), or 1 teaspoon of sodium bicarbonate (baking soda)? Your work will be assessed according the following rubric: Working during the lab (Maximum 5 pts.) Working during the lab (Maximum 5 pts.) Written lab report (Maximum 10 pts.) Follow-up lab (Maximum 5 pts.) lab group will submit one written lab report. This report may be typed or handwritten. It must include the following: 1. (1 pt.) Title starting with the phrase An Experiment to Find Out 2. (1 pt.) names, date, teacher 3. (1 pt.) Introduction In this introductory paragraph (3-5 sentences), provide information related to the experiment, including definitions of key terms and short explanation of major concepts applied in the experiment. 4. (1 pt.) Hypothesis One sentence (per student) stating what was predicted as the answer to the problem given in the Title. (e.g. I predict that Coca-Cola will make radish plants grow faster than water.) 5. (2 pts.) Procedure Numbered steps clearly explaining how you conducted the experiment. Include enough detail that the experiment could be duplicated by others. 6. (2 pts.) Results Use data tables and charts if possible. Show measurements and calculations neatly. 7. (2 pts.) Conclusion Answer the problem stated in the title (e.g. Coca-Cola did not make radish plants grow faster than water). Compare your results with your original hypothesis. Discuss reasons why your results may not be 100% accurate. Discuss reasons why other groups may have obtained different results from yours. Discuss ways that the experiment may be improved if repeated.

4 Working staying on task, no horseplay Working offering original ideas without being bossy, listening to others without judgment, discussing how to divide the work evenly and fairly, while giving everyone a chance to practice various skills during the entire lab period, requiring no during most period, requiring 1-2 approx 50% period requiring 3 or more less than 50% of the lab period requiring no contributes minimally to design and execution of the experiment. does not contribute to design nor execution of the experiment. during the entire lab during approx 80% during approx 50% less than 50% of the lab is not helpful nor communicates effectively with. does not conduct experiment. Perfect score on follow-up lab 80% on 60% on 40% on 20% on 0 on followup lab Name Productive Score Cooperative Score Lab Report Score

5 Chemical quantities Follow-up You may use a calculator, periodic table, and a copy of your own lab report to answer the following questions. 1. During the lab experiment, which substance did you find had the greatest number of atoms in one teaspoon? 2. Given the data below, does one teaspoon of copper have more, fewer, or the same number of atoms as the substance you named in Question 1? Mass of weighing dish Mass of 1 tsp. copper + weighing dish 1.72 g g Follow-up grading rubric: 1 pt correct answer to #1 1 pt correct determination of mass of copper 1 pt- correct # of moles of copper 1 pt. correct # of atoms of copper 1 pt- correct comparison to question 1 answer

Limiting Reactants Lab

Name: Teacher s Name: Class: Block: Date: Partners: Limiting Reactants Lab Purpose: Through experimentation, determine the limiting reactant and the percent yield in a chemical reaction that generates