Convert % solution into mg/l

[naikayaz]

Please provide me answers of the following:

1, How can we convert %age of a solution into mg/l?
2, If we add 20 grams chemical (Solid form) in 80 ml of water and
makeup volume to 100ml then wat will be the percentage of 1 ml
of that solution?
3, Does the concentration of every i m in 100 ml of that solution
remains the same?
4, How to convert % into mg/l of that solution?


Please provide me the answers , i will be thankfull to u.