Answer:
b) pH = 9.25
Explanation:
- NH4+(aq) + H2O(l) ↔ NH3(aq) + H3O+(aq)
- NH3 + H2O ↔ NH4+ + OH-
- 2 H2O ↔ H3O+ + OH-
⇒ Kb = [ NH4+ ] * [ OH- ] / [ NH3 ] = 1.86 E-5......from literature
mass balance NH4+:
⇒ M NH4+ = [ NH4+ ] - [ OH- ]
∴ [ NH3 ] ≅ M NH4+ = 0.26 M
⇒ Kb = (( 0.26 + [ OH- ] )) * [ OH- ] / 0.26 = 1.86 E-5
⇒ 0.26 [ OH-] + [ OH- ]² = 4.836 E-6
⇒ [ OH- ]² + 0.26 [ OH- ] - 4.836 E-6 = 0
⇒ [ OH- ] = 1.859 E-5 M
⇒ pOH = - Log ( 1.859 E-5 )
⇒ pOH = 4.7305
⇒ pH = 14 - pOH = 9.269
6.5 is subtracted from each number.
9 - 6.5 = 2.5
2.5 - 6.5 = -4
-4 - 6.5 = -10.5
-10.5 - 6.5 = -17
or you could think of adding -6.5 to everything if that is easier for you to picture.
Answer:
B) 3.0 g/mL
Explanation:
density formula: mass/volume
15/5=3
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 
<span>1 mole of CO2 = 6.023*10^23 molecules.3 moles of CO2 = 3*6.023*10^23 moleculestherefore, 3 moles of CO2 = 18069*10^20 molecules.
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