Answer:
<em>The grams of hydrogen gas that are released is 0.343 gram</em>
Explanation:
<em>Given that:</em>
<em>2 Na + 2h₂0 ⇒ 2Na0H +N₂</em>
<em>Molecules of Na = 7.9/2.3 = 0.343 mol Na</em>
<em>Now,</em>
<em>2 molecules of Na produces one mole h₂</em>
<em>0.343 mol of Na produce 0.343/2 = 0.1717 mol h₂</em>
<em>h2 = molecules * mw (molecular weight) =0.1717 * 2 =0.343 grams</em>
<em>Therefore the grams of hydrogen gas released is = 0.343 grams</em>
Explanation:
Gravitational potential energy
= mgh
= (5kg)(9.81N/kg)(150m)
= 7357.5J.
According to this formula:
㏑(K2/K1) = Ea/R(1/T1 - 1/T2)
when K is the rate constant
Ea is the activation energy
R is the universal gas constant
and T is the temperature K
when K is doubled so K2: K1 = 2:1 & R = 8.314 J.K^-1.mol^-1
and T1 = 10 +273 = 283 k & T2 = 21 + 273 = 294 k
So by substitution:
㏑2 =( Ea / 8.314) (1/283 - 1/294 )
∴ Ea = 43588.9 J/mol = 43.6 KJ/mol
From the equation it is evident that 2 moles of Sodium metal produces 1 mole of hydrogen gas.
At STP 1mole of any gas occupies a volume of 22.4 liters.
Therefore, 7.80 gives---(7.80×1)/22.4 moles= 0.3482 moles
Since the mole ratio of Sodium to hydrogen is 2:1, then the number of moles of sodium that reacted is given by the following expression.
(0.3482×2)/1 moles which gives 0.6964 moles.
The atomic mass of sodium is 23 thus the mass of sodium that reacted is given by:
mass=no. of moles×RAM
0.6964×23= 16.02 grams.
Answer:
11482 ppt of Li
Explanation:
The lithium is extracted by precipitation with B(C₆H₄)₄. That means moles of Lithium = Moles B(C₆H₄)₄. Now, 1 mole of B(C₆H₄)₄ produce the liberation of 4 moles of EDTA. The reaction of EDTA with Mg²⁺ is 1:1. Thus, mass of lithium ion is:
<em>Moles Mg²⁺:</em>
0.02964L * (0.05581mol / L) = 0.00165 moles Mg²⁺ = moles EDTA
<em>Moles B(C₆H₄)₄ = Moles Lithium:</em>
0.00165 moles EDTA * (1mol B(C₆H₄)₄ / 4mol EDTA) = 4.1355x10⁻⁴ mol B(C₆H₄)₄ = Moles Lithium
That means mass of lithium is (Molar mass Li=6.941g/mol):
4.1355x10⁻⁴ moles Lithium * (6.941g/mol) = 0.00287g. In μg:
0.00287g * (1000000μg / g) = 2870μg of Li
As ppt is μg of solute / Liter of solution, ppt of the solution is:
2870μg of Li / 0.250L =
<h3>11482 ppt of Li</h3>
