ppm and ppb

[sydney101luigi]

2:46 "Do you like that better?" THAT'S WHAT SHE SAID!! Zingg!

[kekothegeko]

thank you for making this video

[sarapiggys12]

thanks it helped!

[brandon429]

Wonderful video rated you 5/5. I have a math inability so I always respected chemists perhaps more than any degree in college. I can't tell you how unbelievably hard it was to get a bs being math challenged constantly~so your videos are now my favorite all over again!

B

[chemistryprofessorpc]

Thank you! You just made my day!

[TheBigT89]

i have another question

calculate the % of calcium in 26 g of oxalate.

[chemistryprofessorpc]

Perhaps your problem with this question is the way in which it is written. You are asked the % calcium in oxalate, but what is is really asking is the percent of calcium in calcium oxalate, CaC2O4.

Now, try it.

[TheBigT89]

i tryed it as a w/w problem

and i got about 31%

[chemistryprofessorpc]

Sounds good to me!

[TheBigT89]

question

mixing 125ml of ethanol (Density= 0.789) with 100ml of water (density=1) gives us a solution with a desity of 0.8945

calculate v/v %

[chemistryprofessorpc]

It is necessary to determine the total volume of the solution made by adding ethanol to the solvent water. This can be done as follows: 1) Find the total mass of the solution (125 mL)(0.789 g/mL) + (100 mL)(1 g/mL) = 198.625 g of solution 2) Use this mass to find the volume of the solution D=M/V V=M/D V=198.625/0.8945 V=222.05 mL 3) To determine the volume of ethanol per 100 mL water, just set up 125 mL ethanol/222.05 mL total X 100 = 56.3% (v/v) The significant digits are iffy I

[TheBigT89]

thank you very much that helped alot