All concentrations are in mass percent so i want to prepare 10 mass % MgCl2 + 20 mass % Methanol of 100 ml solution ( In water) . how many grams of MgCl2 & Methanol in water I need to make 100 ml solution .
10 g of MgCl2 + 20 g methanol + 70 g of water. This is assuming anhdryous magnesium chloride. Chemists usually deal with molar solutions which are more useful. So your original request was something like asking for the speed of light in furlongs per fortnight. Such a solution would commonly be said to contain 10% w/w magnesium chloride and 20 % w/w of methanol.
10 g of MgCl2 + 20 g methanol + 70 g of water. This is assuming anhdryous magnesium chloride. Chemists usually deal with molar solutions which are more useful.
This would give the right mass , wouldn't the density has any sort of influence in it . In normal cases when we deal concentration by mass (gram) , it usually give a combine solution which has value slight higher then (e.g. In this it suppose to become 100 g in total) but in real it become slightly higher . how do I get the right number of grams needed to make a solution . ?
You would have to weight out each of the three components. In order to use a portion of the solution you would have to weight that out as well. The mixed solution would not equal 100 ml in volume for a couple of reasons. As I said chemists use molar solutions because they are more convenient.
The density of methanol would not have any effect since all measurements are by weight only.
At least with a miles/second to furlongs per fortnight, I know or can derive conversion factors. Converting miles to furlongs just multiply by 8. Convert seconds to fortnights, just divide by 86,400 (number of seconds in a day), then divide by 14 (number of days in a fortnight). I was completely lost by the OP, and I took a couple chemistry courses in college! Use it or lose it, I guess...
At least with a miles/second to furlongs per fortnight, I know or can derive conversion factors. Converting miles to furlongs just multiply by 8. Convert seconds to fortnights, just divide by 86,400 (number of seconds in a day), then divide by 14 (number of days in a fortnight). I was completely lost by the OP, and I took a couple chemistry courses in college! Use it or lose it, I guess...
I remember Avagadro's number. And I remember there are 104 elements, and a few other things. College was a long time ago. I tend to remember the upperclassmen throwing firecrackers under our dorm room door all night, and the fried chicken still pink in the center in the cafeteria, more than 1s1 1p1, and all that jazz.