The molar mass of copper is 63.55 g/mol
CaCI2 is for calcium chloride
If a substance has a relatively low melting point (below 400ºF), then it is either molecular polar or molecular non-polar
If a substance has a high melting point, then it is either metallic, covalent network, or ionic
The stronger a substance’s bonds, the higher its melting point
To find them you would have numbers of the elements in percentage or grams then you divide them by their molar mass to get their moles. From there you divide by the smallest number. Round it to two or one sig fig. If you have a number that is for ex. 2.5 you multiply it by 2 to make it whole as well the other whole numbers. Then to find the molecular formula the problem must give you another molar mass and using your empirical formula convert it to its molar mass then you divide them, larger number over smaller number. You should get a number round it to 1 sig fig. Now you use that number and multiply the subscripts on the empirical formula to get the molecular formula.