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Q3: week 9 – 4/1 – 4/5

                                                                                                                                                                                                                                        Jump to:   Tuesday, Wednesday, Thursday, Friday

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_________________________________________________________                                                            Jump toMonday Homework  4/1 – Monday – Mini Spring Break 

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___________________________________________                                                                                     Jump toTuesday Homework / top 4/2 – Tuesday “A” Day

 

 Main focus:

a) To Complete the Solubility CAT 2

b) To begin the percent by mass of a hydrate lab.

     

Period  6:

Lab 20 – Percent by mass of water in a Hydrate .pdf
View Download

1.  Start the heating of a hydrate for Lab 20.

2. Complete Solubility CAT 2 while heating.

3.  Find the final mass of the dried hydrate (anhydrate).

Why did we keep heating and re-weighing?

 

Lab 20: Percent by mass of water in a Hydrate. – 

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Lab 20 – Percent mass of water in a Hydrate

Let’s look at an ionic crystal that has no water called anhydrate.  
 
Lets look at copper (II) sulphate : CuSO4  :

 This image was build by X-ray imaging of salt.

Now it is more complex than the crystal above for NaCl because we have a polyatomic ion in the crystal.

The Yellow is the Sulfur attached to 4 oxygens (red).  The brown color (i think its brown) is the copper.

Notice regular repeating pattern.
The sticks represent the bonds or the attractions between the ions.

Its hard but if look inside the crystal there is one Cu per sulfate ion.

 
Lets look at the formula of the hydrate of the same salt : copper (II) sulphate pentahydrate: 
 
 CuSO45H2O

Notice the Dot between anhydrate and water.  This Dot means “WITH” and not to multiply.   

There are exactly 5 water molecules for every 1 Cu+2 and  1 SO4-2 in the crystal.

 
Lets look at the crystal formation of copper (II) sulphate pentahydrate: 

 You will notice that water (it has 2 white hydrogen atoms) molecules are situated inside the crystals at particular regions in the crystal in exact ratios.  This is a fixed ratio (stoichiometric ratio).

It is hard but you can see the 5 water molecules per 1 copper ion and 1 sulfate ion.

What makes it hard is that the crystal repeats in all directions.

The water can be removed from the salt by heating it.

                                                 CuSO4 • 5H20   ——->    CuSO4  (s)     +      5H20  (g)                                                                                                                                                 Heat                                         
                                                                                                                                                                                                                 Today we will be able to do the following:           
         a) Determine. the mass of your annhydrate (dried hydrate)
       b) Determine the mass of the water (THAT was in your crystal)
       c)  calculate the experimental percent by mass of water:
 
            % by mass =  Mass of the part (mass of water missing)         x     100  
                                    Mass of the whole (mass of original hydrate)
 
         d)  calculate the Theoretical percent by mass of water using the chemical formula of the hydrate:
                 
                                                                                    CuSO4 • 5H20
 
                    Given the formula above, determine the percent by mass of water of the hydrate:
 
                                           Assume you have 1 mole of CuSO4 • 5H20:
 
                                Thus in 1 mole of the hydrate you have 5 moles of water:
 
                                For every one (CuSO4 • 5H20) you have 5 moles of water.
 
                                                                         1               :               5
                                               
                                    Ratios of how many!!! This is why we need a mole theory!                    
 
                               
                          % by massMass of the part (mass of 5 moles of water)         x     100  
                                                   Mass of the whole (mass of 1 mole of hydrate)
 
*Mass of 1 mole of any compound (with a unique chemical formula) is the sum of the atomic masses of all atoms in the formula or molecule. You need the periodic table!
 

____________________________________________________                                                                                jump to:  top                          4/2 – Tuesday’s Homework: – 

1. Read my notes above on today’s lab

2. Read mComplete the worksheet with the video posted below.  When instructed please check the key.

Hydrate Intro worksheet.pdf
View Download

Hydrate Intro worksheet Key.pdf
View Download

I will collect it tomorrow for a quiz grade.

3. Complete the Form Below based on the the topics learned in the video. Most topics are really not new just applied to a new scenario.

              

2 : Hydrate Intro Worksheet Review – 

  
3 : Hydrate Form: THERE IS ONLY ! SUBMISSION TONIGHT!

_____________________________________________________________                                          Jump toWednesday Homework / top      4/3 – Wednesday – B Day – LAB

Main focus: 

a) To calculate the percent by mass of an element in a compound

b) To calculate the percent by mass water in a hydrate experimentally and theoretically

c) To calculate the empirical and molecular formula using percent by mass.

Period  8:
 
1.  Start Lab 21 by heating the hydrate:

 

Lab 21 – Empirical Formula of a Hydrate .pdf
View Download

2.  Complete lab 20 while heating.

3.  Multiple Heatings

4.  Calculate the empirical formula and molecular formula Lesson 

empiri&molec ditto hydrate combination 1314 .pdf
View Download
 
empiri&molec ditto hydrate combination regents 1314 COMPLETE key .pdf
View Download

 

Period  9:

1.  Complete Lab 20:

a) Complete the conclusion questions for Lab 20

b)  To write the conclusion for lab 20.

      a)  Read your objectives and write about what you calculated. – percent by mass of water theoretical and experimental                        values.

       b)  What was the percent error?  Why was it small or large? What were the errors in this lab?

3. Complete Lab 21 data table by calculating the experimental mass of water and hydrate and percent by mass of the hydrate to review last night form.

                                                                    

 

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4/3 –  Wednesday – Homework: –
 

1. Make one more submission to yesterday’s form.  It is NOW on auto reply and you have 2 submissions to fix your grade. I have reposted the form from Tuesday night below.

I will have it graded your first submission and emailed your grade during period 9 today.

 

  
1: Hydrate Form: THERE are 2 SUBMISSIONS  ALLOWED TONIGHT.

______________________________________________                                                                    Jump toThursday Homework / top 4/4 – Thursday “A” Day 

Main focus:   
 

a) To write a empirical formula for a compound given percent by mass data.

b) To write the empirical formula of a hydrate given its percent by mass data.

 

Period  6:   

1. Homework form review

Hydrate Form Key .pdf
View Download

2. Empirical Formula lesson.

empiri&molec ditto hydrate combination 1314 .pdf
View Download
 
empiri&molec ditto hydrate combination regents 1314 COMPLETE key .pdf
View Download

 

3.  Calculate the empirical formula of the magnesium hydrate (lab 21)

 

             MgSO4· ? H2O

Lab 21 – Empirical Formula of a Hydrate .pdf
View Download

 

Todays Lesson Empirical and Molecular formula determination – 

__________________________________________________________________

4/4 –  Thursday – “A” Day homework: 
 

1. Complete question 2,3, and 8 on the worksheet that we started in class today and review with the key below.

empiri&molec ditto hydrate combination 1314 .pdf
View Download
 
empiri&molec ditto hydrate combination regents 1314 COMPLETE key .pdf
View Download

 

I may collect something tomorrow!

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_______________________________________________                                                                                      Jump toFriday Homework 4/5 – Friday – “B” Day – 

Main focus: 

a) To practice and review percent by mass calculations.

b) To review molecular formula vs empirical formula.

c) To determine the emperical formula of a salt.

 *There is a form that goes with this worksheet :

HW questions 1 regents 2015 Key.pdf
View Download
    

I have a form for these questions that I did for a homework assignment in 22-23.

Math Form 1 in my personal G drive.

                                         

Period  6:   

1. Check homework/review

2.  begin the Lab 22 introduction

Lab 22 – Empirical Formula of a SALT .pdf
View Download

Period  7:   

 

1. Lab 22 – The empirical formula of a salt

 

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4/12 –  Friday Homework: –
 

There is no homework this weekend.

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