We have a 5% ethanol solution in water. What is the ratio strength of this solution?

Question

I have no idea how to answer this and the teacher that I have is terrible.  He is not teaching us how to do the calculations.  Please help!

Answer 1

If we have 5% ethanol in water then we have 5% ethanol and 95% water.

The ratio is  0.05:0.95

This can be multiplied by 100 on both sides to give a ratio of

5:95 indicating that for every 5 parts ethanol we have 95 parts water.

Thus, given any total amount we have 5/100 is ethanol and 95/100 is water

 

Example: Given a 350 ml solution of 5% ethanol in water find the ml of

ethanol and the ml of water in the solution:

ethanol = (5/100)(350)=5(3.5) = 17.5 ml ethanol

water = 350 - 17.5 = 332.5 ml water

Note that the solution should be 95% water.. 0.95(350)=332.5

 

Hope this helps. Best of luck. :-)