I’m pretty sure b! hope you get it right
Yes simplify. Anybody educated in chemistry can look at the equation and see that you have Fe+2 and CO3-2 combined to make FeCO3. But you don't need the 2s. Always simplify the subscripts.
By the way, the equation is not fully balanced. Check KBr.
4.42
Because when you divide 129/29.20, you get a long string of numbers. 4.417808219178082...
So you round to the significant figure which in this case is 2 decimal places because 29.20 has 2 decimal places.
PS did you draw that car? Cuz im into drawing cars too.
