You were given a 2.00 g sample of one of the hydrates listed below. The unknown hydrate was heated in a crucible to a constant mass where the anhydrous salt was determined to have a mass of 1.51 g. Unknown Hydrate A BaCl2⋅2H2O , B a C l 2 ⋅ 2 H 2 O B MgSO4⋅7H2O M g S O 4 ⋅ 7 H 2 O C CaCl2⋅2H2O , C a C l 2 ⋅ 2 H 2 O
Answers
Explanation:
D. Correct the errors in these sentences. Make the necessary changes.
1. The Earth rotates on its axes.
2. We saw a hippopotami at the zoo.
3. The old beggar followed the group of college student for alm.
4. A number of disasters crippled the working of the nations.
5. Make sure the radii of the circle equals 5 centimetres.
6. We witnessed a wonderful phenomena a while back.
7. On what bases are you filing this complaint?
8. The teacher stated that this was one of the many criterion for selection into
the team.
this is very inportant
Given:
2.00 g sample of an unknown hydrate
After heating, the mass of anhydrous salt was determined to have a mass of 1.51 g
To Find:
The formula of the salt
Solution:
The unknown hydrate is (c) CaCl₂.2H₂O.
Since after heating only 1.51g of salt is left out of 2.00 g
⇒ The mass of water of crystallization present in the compound = 2.00 - 1.51 = 0.49 g.
Percentage mass of water of crystallization = (Mass of water / Total mass of the compound) X 100
= 0.49 / 2.00 X 100
= 24.5 %
Analyzing the percentage composition of all given options:
A) BaCl₂.2H₂O
Mass of the compound = 208 + 2 X 18
= 244 g
Percentage composition of water of crystallization = 36 / 244 X 100
= 14.75%
B) MgSO₄.7H₂O
Mass of the compound = 120 + 7 X 18
= 246 g
Percentage composition of water of crystallization = 126 / 246 X 100
= 51.21%
C) CaCl₂.2H₂O
Mass of the compound = 111 + 2 X 18
= 147 g
Percentage composition of water of crystallization = 36 / 147 X 100
= 24.5%