Chemistry we are now on the "big M" .... after 50 mL of a .250 M solution of Ca Nitrate (or calcium nitrate)

Question

is combined with 100. mL of a .835 M solution of Ca nitriate, how do you find the molar concentration of Ca(NO3)2 in the solution that is combined.

Please help me I think I failed the past test and I really need to learn this stuff. I dont know if I can ever learn it but I am trying so hard and I dont want an F. :(

Answer 1

M=mol/L

50ml=.05L , 100ml=.1L

.05L*.250mol/L=.0125mol

.1L*.835mol/L=.0835mol

.0125mol+.0835mol=.096mol

.096mol/.15L [total L given in the problem]=.64M

This is not taking into account significant figures.  I don't know if your teacher uses them or not.

Answer 2

M means moles per liter

.25 M means .25 moles per liter

50 ml is .05 liters

total moles = .05 * .25 = .0125 first solution

100 ml is .1 liter

.1 * .835 = .0835 total moles second solution

.0125 + .0835 = combined moles

get the total volume because they are asking for molarity or concentration.

.0125 + .0835/150 ml or .0125 + .0835/.150L =.64 molar