.Answer:
Copper has a mass percent of 17.2% in Copper(ll) perchlorate hexahydrate
Step-by-step explanation:
Start with the chemical formula for the compound. Copper(ll) perchlorate hexahydrate is Cu(ClO4)2*6H2O
The molar mass is 370.4 grams/mole.
To find the mass percent of copper, lets first imagine a convenient mass of 100 g for the compound. Then set up a spreadsheet (or table) that lists the element along with it's molar mass (AMU) and the number of times it appears in the formula (Count). Then multiply the Count times the AMU to get Total AMU for that element. The sum of the Total AMU's is equal to it's molar mass (370.4 g/mole).
The percentage of each element can then be determined by dividing that element's Total AMU by the compound's AMU of 370.4 AMU.
Copper is found to have a mass percent of 17.2% in this compound.
Element Count AMU Total AMU (Count x AMU) Percent*
Cu 1 63.5 63.5 17.2%
O 14 16.0 224.0 60.5%
Cl 2 35.5 70.9 19.1%
H 12 1.0 12.0 3.2%
370.4 grams/mole 100.0%
*Percent is calculated as (AMU/Total AMU)
See the attached spreadsheet (makes calculations easy).