1. Mass of fired crucible and lid (g) 2. Mass of fired crucible, lid, and hydrat

Question

1. Mass of fired crucible and lid (g) 2. Mass of fired crucible, lid, and hydrated salt (g) 3. Instructor's approval of flame and apparatus 40 638 31, 5972 4. Mass of crucible, lid, and anhydrous salt 1st mass measurement (g) 421618 32,6 952 41, 178 32.089 2nd mass measurement (g) 3rd mass measurement (g) 5. Final mass of crucible, lid, and anhydrous salt (8) Calculations 2.5 157 2 S78 1. Mass of hydrated salt (g) 2. Mass of anhydrous salt (g) 1.1251 +#3401929 3. Mass of water lost (g) SAS *_rrar 4. Percent by mass of volatile water in hydrated salt (%) 5. Average percent H2O in hydrated salt (%H2O) mols anhydrous mols H 7. Show calculations on next page. S. Formelr Hydrafe

Explanation / Answer

Solution:

1. Mass of hydrated salt = Mass of fired crucible, lid and hydrated salt - Mass of fired crucible and lid

a. Mass of hydrated salt = 41.0481 - 38.5324 =  2.5157 g

b. Mass of hydrated salt = 41.1149 -  38.5381 =  2.5768 g

Mass of hydrated salt = 2.5157 g 2.5768 g

2. Mass of anhydrous salt = Final mass of crucible, lid and anhydrous salt - Mass of fired crucible and lid

a. Mass of anhydrous salt = 39.9230 -  38.5324 =  1.3906 g

b. Mass of anhydrous salt = 39.9720 -  38.5381 =  1.4339 g

Mass of anhydrous = 1.3906 g 1.4339 g

3. Mass of water lost = Mass of hydrated salt - Mass of anhydrous salt = 2.5462 g - 1.4123 g = 1.1340 g

a. Mass of water lost = 2.5157 -  1.3906 =  1.3906 g

b. Mass of water lost = 2.5768 -  1.4339 =  1.4339 g

Mass of water lost = 1.1251 g 1.1429 g

4. Percentage by mass of volatile water in hydrated salt = (Mass of water lost / Mass of hydrated salt) x 100%

a. Percentage by mass of volatile water in hydrated salt = (1.3906 / 2.5157) x 100% = 55.28%

b. Percentage by mass of volatile water in hydrated salt = (1.4339 / 2.5768) x 100% = 55.65%

Percentage by mass of volatile water in hydrated salt = 55.28% 55.65%

5. Average percent water in hydrated salt = Average of Percentage by mass of volatile water in hydrated salt

= (55.28% + 55.65%) / 2 = 55.46%

Average percent water in hydrated salt = 55.46%

6. Standard deviation of %Water = [(a. Percentage by mass of volatile water in hydrated salt - Average percent water in hydrated salt)2 + (b. Percentage by mass of volatile water in hydrated salt - Average percent water in hydrated salt)2 / (2-1)]1/2

= [(55.28% - 55.46%)2 + (55.65% - 55.46%)2 / (2-1)]1/2 = 0.0026%

Standard deviation of %Water = 0.0026%

7. Relative standard deviation of %Water in hydrated salt = (100 x Standard deviation of %Water) / Average percent water in hydrated salt = (100 x 0.0026%) / 55.46%= 0.0047%

Relative standard deviation of %Water in hydrated salt = 0.0047%

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