OL Lab 3: Stoichiometry: Avogadro’s number and molecular calculations / Solution Preparation: From salt to solution

Learning Objectives:

· Explain the relationship between mass, molecular weight, and numbers of atoms or molecules and perform calculations deriving these quantities from one another

· Perform mass-to-mass stoichiometric calculations
via conversions to moles

· Identify the limiting and excess reagents in a chemical reaction

· Calculate the theoretical, actual and percent reaction yield

· Define Avogadro’s number and describe the mole quantification of matter

· Explain relationship between mass, molecular weight, and numbers of atoms or molecules

· Perform conversion and derivations calculations using key molecular quantity parameters

· Define Avogadro’s number and describe the mole quantification of matter

How many moles of sand grains has the Sahara desert? What is the only equation you´ll ever need in chemistry? The short stoichiometry simulation will help you answer those questions! Follow the footsteps of great chemists and learn about key molecular parameters based on one and only star of chemistry calculations: Avogadro’s Law!

Concept mole and Avogadro’s Law:

Your first mission in this short simulation is to familiarize yourself with the concept of mole and the way of counting molecules of substances using the one and only Avogadro’s Law. You will learn how to convert huge numbers of particles into handy Avogadro’s number, extensively used by all chemists around the world!

Chemical units relationship:

Next, you will explore the relationship between mass, molecular weight, and number of atoms. This magical equation will enable you to perform derivations of molecular quantity parameters for various chemical substances. You will feel like Marie Curie analysing chemical dependencies of chemicals in her french laboratory! Part 1: Complete the Labster lab: Stoichiometric calculations: Identify an unknown compound using gravimetric analysis

Glassware and quantitative transfer
Moving on to the second workbench, you will explore and determine what glassware will be appropriate for you to use. Your lab guide and mentor, Dr. One, will walk you through the process of preparing the solution. You will have the freedom to use the equipment as you like, but only by following Dr. One’s instructions will you be successful in making the right solution. To make sure you can always redo the essential steps of the process, Dr. One will provide you with a fantastic reset button, so you can try again if you make a mistake.

Solve the preparation
In the end, only by carefully ensuring that the right amount of water and ammonium chloride is used can you make the correct solution. Are you prepared for solving how to perform a Solution Preparation?

Part 1: Complete the Labster Lab: Stoichiometry: Avogadro’s number and molecular calculations

Complete all activities and answer all questions within the lab and then complete the questions below:

Purpose: Describe in complete sentences and in your own words, the purpose of this experiment.

Observations: Record three observations from the simulation.

I.

II.

III.

1. How do you convert between grams and moles of a specific molecule? Give a specific example to illustrate.

2. How do you convert between moles of one substance and moles another substance?

3. Balance the following chemical equation:

Na2CO3(aq) + CaCl2(aq) → CaCO3(s) + NaCl(aq)

4. Use the balanced chemical equation from the last question to solve this situation: You combine 0.5 moles of Na2CO3 with enough CaCl2 that your compound reacts completely. How many moles of NaCl would you expect this reaction to produce? Show all work below.

Part 2: Complete the Labster Lab: Solution Preparation: From salt to solution

Complete all activities and answer all questions within the lab and then complete the questions below:

1. In this lab, you learned how to prepare solutions with a precise concentration. Where in your nursing career might this skill be needed?

2. Which piece of glassware did you use to prepare your solution in this lab and why?

3. Calculate how many grams of NaCl are required to make 100 mL of a 1 M NaCl solution. Show your work in the space below.

Reflection: Consider what you learned from these simulations. Reflect on three to four key concepts that you learned in this lab exercise. How could the lessons learned in this virtual lab relate to a real world situation in the community/world or your future career? Be specific in your answer (this should require 5-10 sentences).

Grading Rubric: