What is the concentration of a solution formed by diluting 25.0 ml of a 3.2 m nacl solution to 135.0 ml?

a) 17 m nacl
b) 0.59 m nacl
c) 0.50 m nacl
d) 2.7 m nacl

B) 0.59 M NaCl.

Explanation:

∵ (MV) before dilution = (MV) after dilution.

∴ M after dilution = (MV) before dilution / V after dilution = (3.2 M)(25.0 mL)/(135.0 mL) = 0.5926 M ≅ 0.59 M.

im pretty sure its b

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol