Question
The table shows the relative atomic masses of some common elements. Use this information to work out the relative formula mass of the compound with the formula shown below the table. Enter a number Element & Relotive atomic mass hydrogen & 1 carbon & 12 nitrogen & 14 oxygen & 16 sodium & 23 magnesium & 24 phosphorus & 31 sulfur & 32 chlorine & 35.5 calcium & 40 iron & 56 [ mathrm(Ca)_(3)(mathrm(PO)_(4))_(3) ]
Answer
4
(284 Votes)
Yasmin
Master · Tutor for 5 years
Answer
310
Explanation
The relative formula mass (Mr) of a compound is simply the sum of the relative atomic masses (Ar) of all the atoms shown in the formula. In the given formula Ca3(PO4)2, the count for each element in the compound is as follows: Ca ->3 ,P ->2 and O->8 (O4 * 2). Hence the Symbolic Formula for prompting by Sum is: (Number Atoms × Atomic Weight)+ .......Now if we refer to the table we are provided with relative atomic masses of various elements, taking concerned elements from it: Ca=40, P=31 and O=16. Therefore, we could deduce the mass is as follows: (3*40) + (2*31) + ( 8*16)