How do I make up 40cm3 of salt solution with a 2.0M salt?

Question

Hi

If I wanted to make a 40cm3 salt solution from 2.0M salt, do I pur out 20cm3 of the 2.0M salt and dilute it with 20cm3 of water?
Sorry to ask probably a stupid question, but it's been 16 years since my chemistry lessons at school and am taking an evening class in biology, not chemistry!

Thanks for your help

shetajan

Answer 1

So you have a solution 1.0 M . In fact 20 mL of solution 2.0 M contain 0.04 moles ( in 1000 mL there are 2 moles in 40 mL there are 0.04 moles). Total volume is 40 mL=0.04 L so
M= 0.04/0.04=1M
If you need another molarity tell me and I will answer

Answer 2

As a qualified physique piercer I havent got here upon any distinction between using sea salt and cooking salt. the only distinction is the feel of the product. you fairly shouldnt be using a cleansing answer for greater desirable than 3 weeks after a piercing till you have an infection becuase you may certainly do greater harm by over cleansing it.

Answer 3

Impossible to make what you want. If you have 20cm^3 of 2.0M and you add water , you dilute automatically and the result will be always less than a concentration of 2.0M

Answer 4

does this make sense to people? i'm having a hard time