Question

Can Someone help me on chem questions Im trying to study for finals but Im struggling on some questions

Answer 1

How many milliliters of a 5.00 M HCl solution would be needed to prepare 250.0 mL of a 0.400 M HCl solution?

Answer 2

we need to get to 250mL of 0.4M HCl so we need 0.1 moles of HCl

to get this out of a 5M HCl solution we'll need 0.1/5 litres which is 20mL

Answer 3

can you follow that?

Answer 4

nope

Answer 5

i'll go thru it step by step tomorrow

Answer 6

If we need to get to and end result of 250ml of 0.4M HCl then we use the molarity formula
M=n/V to work out the no of moles required which is 0.4M x 0.25L = 0.1 moles

So to get this no of moles out of a 5M HCl solution we'll need 0.1moles/5M = 0.02L

or 20mL