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pH calculation. Steps and answer provided, need help with one step please?
A 5.0cm^3 sample of 0.135 moldm^3 hydrocholoric acid is added to 995cm^3 of water. Calculate the pH of the solution formed.
mol HCl = (5.0 ×10^-3) × 0.135 = 6.75 × 10^-4
-log[6.75 x 10^-4] = 3.17
pH = 3.17
My question is, why do you do this bit: (5.0 ×10^-3), and where does the x10^-3 come from?
Thank you!
1 Answer
- skipperLv 71 decade agoFavorite Answer
dm^3 = liters (1000 cm^3)
moles = liters x molarity
HCl concentration was 0.135 mole/dm^3 = 0.135 mol/liter
5.0 cm^3 = 0.0050 liters = 5.0x10^-3 liters = 5.0x10^-3 dm^3