So what you’re going to do is basically the + and - in each top hand corner is the charge of compound, so for example Li has a charge of +1 while Br has a charge of -1 , to write the formula you need to get the charges to cancel out ( equal zero) so luckily this was easy because -1 +1 =0 ! So it would be LiBr. Though for another example Al has a charge of 3+ while br has a charge of -1 and these do not equal zero, so as a result you have to add more br making the Formula AlBr3! Hope this helps!
The Milky Way is a SBc barred spiral galaxy.
Carbon dioxide is a gaseous molecule made up of the elements, C and O. Each mole of carbon dioxide has one mole C and two mole oxygen atoms.
Molar mass of carbon dioxide (
)=
Percentage by mass of carbon = 
Percentage by mass of oxygen = 
Therefore C is 27.3 % and O is 72.7 % by mass in 1 mol CO