Choose ONE of these and do them on the history of atoms please <3
1 answer:
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Answer : (C) Hafnium is the most likely identity of the given substance.
Solution : Given,
Mass of given substance (m) = 46.9 g
Volume of given substance (V) = 3.5
First, find the Density of given substance.
Formula used :
Now,put all the values in this formula, we get
= 13.4 g/
So, we conclude that the density of given substance (13.4 g/) is approximately equal to the density of Mercury and Hafnium (13.53 and 13.31 g/
respectively).
According to the question the substance is solid at room temperature but Mercury is liquid at room temperature. So, Mercury is not identical to the given substance.
Another element i.e, Hafnium is the element whose density is approximately equal to the given substance and also solid at room temperature. And we know that the melting point of solid is high.
So, Hafnium is the most likely element which is the identity of the given substance.
Answer:
Molar percent of sodium in original mixture is 88,50%
Explanation:
The last reaction is:
BaCl₂ + Na₂SO₄ → BaSO₄ + 2 NaCl
The moles of BaCl₂ are:
0,132L × 3,80M = 0,502 moles of BaCl₂
As the amount of BaCl₂ is the maximum possible to produce BaSO₄, the moles of BaCl₂ must be the same than moles of Na₂SO₄.
0,502 moles of BaCl₂ ≡ 0,502 moles of Na₂SO₄
These moles of Na₂SO₄ comes from:
2 Na + H₂SO₄ → Na₂SO₄ + H₂
As the reaction is in stoichiometric amounts, moles of Na are twice the moles of Na₂SO₄
0,502 moles of Na₂SO₄ ×× 22,99 g/mole = 23,08 g of Na
Molar percent of sodium in original mixture is:
= <em>88,50% </em>
I hope it helps