I need help with my chemistry experiment here\'s my information, I have 2.0 g of

ID: 821528 • Letter: I

Question

I need help with my chemistry experiment here's my information, I have 2.0 g of anhydrate KAl(SO4)2:

Mass of aluminium cup: 2.4 g

Mass of aluminium cup and alum: 4.4 g

Mass after heated 5 min: 4.0 g

Mass after second heating: 3.8 g

Mass after second heating: 3.5 g

Mass of alum: 3.5 g - 2.4 g = 1.1 g

Mass of water lost: 4.4 g - 2.4 g - 1.1 g = 0.9 g

1) Determine the moles of anhydrate KAl(SO4)2

2) Determine the moles of H2O

3) Calculate the ratio of moles H2O to moles KAl(SO4)2

4) Calculate the percent water: mass of water lost / mass of hydrated salt * 100%

mass of KAl(SO4)2 = 257 gm/mol

Ans 1) moles of KAl(SO4)2 = 3.5/257 = 0.0136 moles

Ans 2) 1.1/18 = 0.06111

Ans 3) Ratio of moles of H20 to KAl(SO4)2 = 0.06111/0.0136 = 4,4933

Ans 4) % = (0.9/3.5)*100 = 25.71 %

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