Answer:
pH = 3.37
Explanation:
A weak acid as lactic acid in a solution with sodium lactate (Its conjugate base) produce a buffer. The pH of this buffer is obtained using H-H equation:
pH = pKa + log [A-] / [HA]
<em>Where pH is the pH of the buffer,</em>
<em>pKa is 3.86</em>
<em>And [] could be taken as the moles of A- = Sodium lactate and HA = Lactic acid.</em>
<em />
Moles A-:
40.0mL = 0.0400L * (0.75mol / L) = 0.030 moles A-
Moles HA:
75.0mL = 0.0750L * (1.25mol / L) = 0.09375 moles HA
Replacing:
pH = 3.86+ log [0.030 moles A-] / [0.09375 moles HA]
<h3>pH = 3.37</h3>
<em />
<span>0.06355391 mol
The balanced equation for the reaction is
Na2B4O7*10H2O + 2 HNO3 = 2 NaNO3 + 4 H3BO3 + 5 H2O
So for each mole of Borax to neutralize, it takes 2 moles of HNO3.
Calculate number of moles of Borax
0.2619 g / 381.372 g/mol = 0.0006867 mol
Moles of HNO3 used = 0.0006867 mol * 2 = 0.0013734 mol
Molarity is defined as moles per liter so divide the number of moles used by the volume in liters. So
0.0013734 / 0.02161 = 0.06355391 mol</span>
Answer:
Explanation:
The pressure at the bottom of the tank is:
The force exerted on the circular bottom is:
![F=(73581.921\,Pa)\cdot (\frac{\pi}{4} )\cdot [(12\,ft)\cdot (\frac{0.305\,m}{1\,ft} )]^{2}](https://tex.z-dn.net/?f=F%3D%2873581.921%5C%2CPa%29%5Ccdot%20%28%5Cfrac%7B%5Cpi%7D%7B4%7D%20%29%5Ccdot%20%5B%2812%5C%2Cft%29%5Ccdot%20%28%5Cfrac%7B0.305%5C%2Cm%7D%7B1%5C%2Cft%7D%20%29%5D%5E%7B2%7D)
Gold is a mixture Becasue it contains more than one element
Molar mass of LiBr (mm )= 86.845 g/mol
Molarity ( M ) = 4 M
Mass of solute ( m ) = 100 g
Volume ( V ) = in liters ?
V = m / mm * M
V = 100 / 86.845 * 4
V = 100 / 347.38
V = 0.2875 L
hope this helps!.
