Answer: 2mg
Part per million is unit that equal to mg/kg of water or simply

. In this case, you asked how much NaCl needed and know the volume of water(100mL), concentration(20ppm or 20 mg/kg) and water density.
Then, the equation would be
concentration = NaCl weight/ water weight
20 x

mg= NaCl weight/ (100ml x 1g/ml)
NaCl weight= 20x

mg/kg x 100g
NaCl weight= 2000 x

g
NaCl weight= 2x

g = 2mg
TMS has 12 protons which are all equivalent and four carbons, which are also all equivalent. This means that it gives a single, strong signal in the spectrum, which turns out to be outside the range of most other signals, especially from organic compounds.
1 mole H2O ---------------------- 6.02x10²³ molecules
4 moles H2O--------------------- y molecules
y = 4 * 6.02x10²³
y = 2.4x10^24 molecules
answer b
hope this helps!.
5,700
That’s half
Hope that helps