Urgent help needed

[Gamewizard]

Hi I am making a formulation and i dont know how much water to add in there.

 

The base mixture is is 2000g in total, and has 736.716 g of water (% w/w is 36.8358)

 

 

I need to make the mixture to be 5% of a raw material, 6% of a raw material, and 8% of a raw material. I have calculated how much raw material i need to add in grams for example, 5% of raw material A mixture will contain 100g of material A, but i am having problems with calculating the amount of water i need to add to each of these % mixtures.

can anyone help me help calculate the amount of water in grams i need to add to the 5% mixture ?

 

help please

 

 

[John Cuthber]

In general, you can't.

If i want to make 100 ml of a 5% w/v solution of salt in water I know that I need 5 g of salt, but I don't know how much water I will need.

Its going to be close to 100 ml.

95 ml is probably a better bet.

100 ml - whatever the volume of 5g of salt is would be better still, but there's no guarantee that it will be right.

 

 

That's why someone invented the volumetric flask.

You put 5 g of salt in it and some water to dissolve it. Then you wait for it to come back to room temperature, then you fill the flask up to the 100 ml mark.

 

There isn't really enough information in your post to say exactly what you need to do because you have not said if those percentages are all m/m m/v or what.

[Gamewizard]

Sorry, yes they are all w/w %

[John Cuthber]

It's still not clear what you are trying to do.