How can i find the percentage composition by mass of elements in a compound?
1. Calculate the molar mass of the compound as follows: relative atomic mass of first element (Si) times subscript (1)+ relative atomic mass of 2nd element (Cl) times subscript (4). If the compound has more than 2 elements add them. 2. Calculate the amount of each element in one mol of compound. For example: for Cl in the first compund is atomic relative mass of Cl times 4. 3. Finally, to find out the percentage compostion by mass for each element divide whatever you derived in 2. to whatever you derived in 1. and multiply all this to 100. Here you find an example for the first compound: atomic relative mass of Si: 28 atomic relative of Cl: 35.5 total molar mass of compound: 28*1+35.5*4=170 amount of Si in this compound is: 28*1=28 giving percentage composition by mass of Si: 28/170*100=16.47% amount of Cl in this compound is: 35.5*4=142 giving percentage composition by mass of Cl: 142/170*100=83.53% Checking: 16.47%+83.53%=100% If it is not clear enough of you need further assistance
