If your username is Mrs. L, Lexi R., moouers, or Maggie, do NOT answer my question.
Which is the percent composition of bromine in the compound NaBr?
A) 81.6%
B) 79.9%
C) 84.1%
D) 77.7%
2) The name of a hydrate is calcium chloride dihydrate. What is its formula?
A) CaCl2•H4O2
B) CaCl2•2H2O
C) 2CaCl2•H2O
D) CaCl2•H2O
Which is the percent composition of bromine in the compound NaBr?
A) 81.6%
B) 79.9%
C) 84.1%
D) 77.7%
2) The name of a hydrate is calcium chloride dihydrate. What is its formula?
A) CaCl2•H4O2
B) CaCl2•2H2O
C) 2CaCl2•H2O
D) CaCl2•H2O
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1) D
2) B
2) B
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1(22.99gNa) + 1(79.90gBr) = 102.89gNaBr
(79.90gBr / 102.89gNaBr) x 100% = 78.0%
Depending on the periodic table you are using, this percentage may be off by a bit. I would say the answer is D.
Calcium chloride dihydrate
Ca has a charge of +2
Cl has a charge of -1
Therefore, CaCl2 would cause the charges to neutralize each other.
Dihydrate is two molecules of water, so since water is denoted H2O, you would just add a two coefficient to the front.
So the full answer would be CaCl2•2H2O (or letter B).
(79.90gBr / 102.89gNaBr) x 100% = 78.0%
Depending on the periodic table you are using, this percentage may be off by a bit. I would say the answer is D.
Calcium chloride dihydrate
Ca has a charge of +2
Cl has a charge of -1
Therefore, CaCl2 would cause the charges to neutralize each other.
Dihydrate is two molecules of water, so since water is denoted H2O, you would just add a two coefficient to the front.
So the full answer would be CaCl2•2H2O (or letter B).
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1)
D) 77.7%
bcoz molecular wt of Na is 23
molecular wt of Br is 80
and % of Br=80/103=77%
2)
B)CaCl2•2H2O
bcoz dihydrate means two water molecules
D) 77.7%
bcoz molecular wt of Na is 23
molecular wt of Br is 80
and % of Br=80/103=77%
2)
B)CaCl2•2H2O
bcoz dihydrate means two water molecules