The periodic table is one of the most important tools in the history of chemistry. It describes the atomic properties of every known chemical element in a concise format, including the atomic number, atomic mass and relationships between the elements. Elements with similar chemical properties are arranged in columns in the periodic table.
The table thus is a quick reference as to what elements may behave the same chemically or which may have similar weights or atomic structures.
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Answer:

Explanation:
Hello.
In this case, given the formula:

Whereas E is the energy, h the Planck's constant and u the frequency of the photon. Thus, solving for it, we obtain:

Or also:

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Hey there !
<span>Balanced equation:
1 MgS +1 Na2O = 1 Na2S + 1 MgO
</span>
MgS = 1
Na2O = 1
Na2S = 1
MgO = 1
Answer D
Answer:
12
Explanation:
You will need a chemical equation with masses and molar masses, so let’s gather all the information in one place.
: 258.21 18.02
KAl(SO₄)₂·xH₂O ⟶ KAl(SO₄)₂ + xH₂O
Mass/g: 4.74 2.16
Step 1. Calculate the mass of the KAl(SO₄)₂.
Mass = 4.74 g – 2.16 g = 2.58 g.
Step 2. Calculate the moles of each product.


Step 3. Calculate the molar ratio of the two products.

1 mol of KAl(SO₄)₂ combines with 12 mol H₂O, so x = 12.