Answer:
a. Raise the pH slightly
Explanation:
We know that
Pka of HNO2/KNO2 =3.39
Moles of HNO2 in the buffer=0.247 mol/L×1L=0.247 moles
Moles of NO2-=0.329mol/L×1L=0.329 moles
If 0.271 moles of Ca(OH)2 is added it will neutralise 0.136 moles of acid ,HNO2,remaining HNO2=0.247-0.136=0.111 moles
Moles of NO2- will increase as 0.0333 moles Ca(NO)2 will be formed =0.0333+0.036=0.0693 moles
pH=pka+log [base]/[acid] {henderson -hasselbach equation}
=3.39+log (0.0693/0.0317)=3.39+0.34=3.73
pH=3.73
Answer: Potential energy is converted to kinetic energy and back again.
Explanation:At points 1 and 3, the pendulum stops moving, and its mechanical energy is purely potential. At point 2, the pendulum is moving the fastest, and its mechanical energy is purely kinetic. Therefore, as the pendulum moves from point 1 to point 3, its potential energy is first converted to kinetic energy, then back to potential.
NaH(s)+ H2O (l)=>NaOH(aq)+H2(g)
You want to calculate the mass of NaH, I assume. Otherwise, the question isn't clear. It simply says calculate the mass(??)
So, calculate the moles of H2 gas that satisfy the conditions of 982 ml at 28ºC and 765 torr. But you must subtract the vapor pressure of water at 28º to get the actual pressure of the H2 gas. So, the actual conditions are 982 ml (0.982 L) and 301 K and 765-28 = 737 torr.
PV = nRT
n = PV/RT = (737 torr)(0.982 L)/(62.4 L-torr/Kmol)(301 K)
n = 0.0385 moles H2
moles NaH needed = 0.0385 moles H2 x 1 mole NaH/mole H2 = 0.0385 moles NaH required
mass of NaH needed = 0.0385 moles x 24 g/mole = 0.925 g NaH
Brainliest Please :)
Answer:
Your answer should be 15.68 grams.
Explanation:
Seeing as 1 mole has a mass of 56 g, 56*0.28 would get you 15.68 g.
