Example #1 write the chemical formula for Calcium Oxide
Step 1
-Find the Atomic symbol of the metal and non-metal on the periodic table
CaO
Step 2
Find the charges for Calcium and Oxygen
which are Ca 2+ and O 2-
Step 3
Balance out the charges
They are already balanced out
Here´s the chemical formula for Calcium Oxide
CaO
Example 2 write the chemical formula for Aluminum Oxide
Step 1
-Find the Atomic symbol of the metal and non-metal on the periodic table
A
l
O
Step 2
Find the charges for Aluminum and Oxygen
Which are Al 3+ and O 2-
Step 3
Balance out the charges
You need 2 Aluminum and 3 Oxygen to balance the charges
Al 3+ O 2-
Al 3+ O 2-
= 6 + O 2-
= 6-
Step 4
If you need more then one element to balance out the charges you identify that by using subscripts
Heres your chemical formula for Aluminum Oxide

Answer:
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I hope this helps!
What mass of the following chemicals is needed to make the solutions indicated?
Answer:
271.6g
Explanation:
The mass of the chemicals need to make the needed solution can be derived by obtaining the number of moles first.
Given parameters:
Volume of solution = 1L
Molarity of HgCl₂ = 1M
number of moles of HgCl₂ = molarity of solution x volume
= 1 x 1
= 1 mole
From;
Mass of a substance = number of moles x molar mass;
we can find mass;
Molar mass of HgCl₂ = 200.6 + 2(35.5) = 271.6g/mol
Mass of the substance = 1 x 271.6 = 271.6g