One of the most important characteristic of a metal is its density. As density is the mass of any substance per unit volume. If one can measure the mass of the given shiny metal and its volume then the density of the metal can be determined. The density if matches with the density of the real gold then one can determine the metal is gold or not. The other experiments given will not work in any condition as-
1. Gold doesn't react with water.
2. The hardness of any metals are more than the non-metals and it is not at all an unique property of any metal.
3. All the metals usually reacts with acids or bases with more or less extent. thus it cannot identify the metal is gold or not.
4. The magnetic property is an inherent property of metal. There are several metals which shows magnetic property. Thus gold cannot be identified by this way.
It protects the alloy against rusting.
Stainless steels contain more than 10% chromium by mass, but almost no carbon. Stainless steels are durable because chromium forms an oxide that protects the steel from rusting. But stainless steel is more brittle than steels that contain more carbon.
Molar mass of sodium chloride is 22.99 g/mol (Na+) + 35.45 g/mol (Cl-) = x g/mol. Then take the mass of sodium chloride sample 5 grams and divide by molar mass to get the number of moles. Take this number and multiply it by Avogadro’s number (6.22*10^23 molecules/mol). You now have the amount of molecules in 5 grams of NaCl.
B. New atoms are formed as products.
Q=44.0 ct
p=3.51 g/cm³
Δq=0.200 g/ct
m=q×Δq
v=m/p=q×Δq/p
v=44.0×0.200/3.51≈2.5 cm³
C. 2.5 cm³
