B) The light source can be seen from the penumbra.
The answer would be 0.8 mol of x left over....
AND THATS IS WHY...refer to the pic below...
See if it is clear enough...
618.454. I just did the equation in a character oops.
There are 8.786 g
<h3>Further explanation
</h3>
The mole is the number of particles contained in a substance
1 mol = 6.02.10²³
2.30 x 10²³ atoms in Na :

mass :

Molar mass :
NH₃ = 17.0 g/mol
(NH₄)₂SO₄ = 132 g/mol
2 NH₃ + H₂SO₄ = (NH₄)₂SO₄
2 x 17 g NH₃ ------------ 132 g <span> (NH</span>₄)₂SO<span>₄
</span>( mass NH₃) ------------ 1.90 x 10⁵ <span> (NH</span>₄)₂SO<span>₄
( mass NH</span>₃) = (1.90 x 10⁵) x 2 x 17 / 132
<span>
( mass NH</span>₃) = 6460000 / 132
<span>
( mass NH</span>₃) = 48939.39 g
<span>
in kg :
48939.39 / 1000 = 48.93 kg = 4.893 x 10</span>¹ kg
<span>
hope this helps!
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