Answer:
28.11g
Explanation:
Step 1:
Background understanding:
From Avogadro's hypothesis, 1 mole of any substance contains 6.02x10^23 atoms. This also indicates that 1 mole of helium (He) contains 6.02x10^23 atoms.
1 mole of He = 4g
Step 2:
Determination of the mass of He that contain 4.23x10^24 atoms. This is illustrated below:
4g of He contains 6.02x10^23 atoms.
Therefore Xg of He will contain 4.23x10^24 atoms i.e
Xg of He = (4x4.23x10^24)/6.02x10^23
Xg of He = 28.11g
Therefore, 28.11g of He contains 4.23x10^24 atoms
<span>The symbol for hydronium ion concentration is H+. </span><span>There are quite a few
relationships between [H+] and [OH−]
ions. And because there is a large range of number between 10 to 10</span><span>-15</span><span>
M, the pH is used. pH = -log[H+] and pOH = -log[OH−]. In aqueous solutions, </span><span>[H+
][OH- ] = 10-14. From here we can derive the values of each concentration.</span>
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!
</span><span>
</span>
Answer: Nuclei combine to form a heavier nucleus, releasing energy.
Explanation: e.g two deuterium nucleus (Hydrogen-2 isotopes) forms an He nucleus and energy is released.
Answer: The best way to promote the process are:
--> Add a bit of solid as a seed crystal.
--> Scratch the bottom of the flask gently with a stirring rod.
Explanation:
A crystal growth is seen is SUPERSATURATED solutions which contains more solute than it can normally dissolve at that given temperature. It is usually very UNSTABLE and capable of releasing the excess solute if disturbed, either by shaking or seeding with a tiny crystals.
Crystallization can be used for the separation of two salts with different solubilities as well as for purification of a soluble salt that contains insoluble solid impurities. Recrystallization improves the validity of the process. Crystallization can be initiated by:
--> Scratching the bottom of the flask gently with a stirring rod: scratching initiates crystallization by providing energy from the high-frequency vibrations.
--> Adding a bit of solid as a seed crystal: Seed crystals create a nucleation site where crystals can begin growth.
