The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 × 10²³ (which is used as a standard in the world of moles).
Now,
if 6.02 × 10²³ atoms are found in 1 mole of Mg
then let 6.98 × 10²⁴ atoms are found in x
⇒ x = (6.98 × 10²⁴) ÷ (6.02 × 10²³)
= 11.595 mol
Also,
Mass = Mole × Molar Mass
∴ Mass of Mg = 11.595 mol × 24 g / mol
= 278.27 g
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The mass of a sample of 6.98 × 10</span>²⁴ atoms of magnesium (Mg) would contains 278.27 g
Answer:
The third reaction
(2NaOH + NiCL2 ---> 2NaCl + Ni(OH)2)
Explanation:
By definition, a precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined.
(Source: lumenlearning)
From the 4 options, we can eliminate the first and second one immediately because there is no formation of an insoluble salt.
Then, the last one can also be eliminated because even though there is insoluble solid formed, but it is not a salt, and, the reactants are not solutions too. In fact, the last one is a displacement reaction. A more reactive metal displaces a less reactive metal to form an ion.
Since the third reaction matches the definition of precipitation reaction, this is the answer.
Answer: when the solar system settled into its current layout about 4.5 billion years ago, earth formed when gravity pulled swirling gas & dust in to become the third planet from the sun. like its fellow terrestrial planets, earth has a central core, a rocky mantle, & a solid crust.
A, B, and D. You already answered the first one, so I wouldn't think this would be too hard
:)
