Stoichiometry

Stoichiometry

Review Questions

Steps to solving these types of problems

• STEP 1: When you start the problem with GRAMS, convert to moles using the molar mass. (1 mol=molar masss)

• STEP 2: Use the balanced chemical equation to convert from given substances to wanted substance. The balanced chemical equation is the MOLE relationships between the substances.

• STEP 3: If the problem is asking you to express the answer in grams, use the molar mass to convert from moles to grams. (1 mol-molar mass)

Poll

Does the previous slide provide guidance to solving the problems?

• yes

• no

• I'm not sure

Open Ended

Let's try a problem together. This is the basis for all the other problems of this type. It's a mol-mol conversion.

Given the equation,  2 NaCl  $\rightarrow$   2 Na +  $Cl_2$  if you have 15 moles of NaCl, how many moles of Na can be formed?

Work out this problem on paper and type your answer in. 

Did you get 15 moles Na?

• How do you know?

Multiple Choice

Given the following equation, 2 NaCl  $\rightarrow$  2 Na +  $Cl_2$ , how many grams of Chlorine can be formed if you start out with 5 grams of NaCl?

• 3 grams  $Cl_2$  

• 30 grams  $Cl_2$  

• I have no idea how to solve this problem!