The two ways to measure the sand in a sand castle are by counting the number of pails of sand used to build the castle and by determining the mass of the sand used in building the castle. The first method makes use of the volume of the pail to determine the amount of sand while the second method is a more quantitative way.<span />
Answer:
The equilibrium expression is:
CoC2O4(s)⇌Co2+(aq)+C2O2−4(aq)
For this reaction:
Ksp = [Co2+][C2O2−4]=1.96×10−8
Explanation:
Batteries will not clot if cobalt ions are removed from its cells. Some blood collection tubes contain salts of the oxalate ion,
C2O2−4
, for this purpose. At sufficiently high concentrations, the calcium
and oxalate ions form solid, CoC2O4·H2O (which also contains water bound in the solid). The concentration of Co2+ in a sample of blood serum is 2.2 × 10–3M. What concentration of
C2O2−4
ion must be established before CoC2O4·H2O begins to precipitate.
CoC2O4 does not appear in this expression because it is a solid. Water does not appear because it is the solvent.
Solid CoC2O4 does not begin to form until Q equals Ksp. Because we know Ksp and [Co2+], we can solve for the concentration of
C2O2−4
that is necessary to produce the first trace of solid:
Answer:
The most effective buffer at pH 9.25 will be a mixture of 1.0 M NH3 and 1.0 M NH4Cl
Explanation:
Step 1: Data given
pH of a buffer = pKa + log ([A-]/[Ha])
a mixture of 1.0 M HC2H3O2 and 1.0 M NaC2H3O2 (Ka for acetic acid = 1.8 x 10-5)
pH = -log( 1.8 * 10^-5) + log (1/1)
pH = -log( 1.8 * 10^-5)
pH = 4.74
a mixture of 1.0 M NaCN and 1.0 M KCN (Ka for HCN = 4.9 x 10-10)
pH = -log( 4.9 * 10^-10) + log (1/1)
pH = -log( 1.8 * 10^-5)
pH = 9.30
a mixture of 1.0 M HCl and 1.0 M NaCl
The solution made from NaCl and HCl will NOT act as a buffer.
HCl is a strong acid while NaCl is salt of strong acid and strong base which do not from buffer solutions hence due to HCl PH is less than 7.
a mixture of 1.0 M NH3 and 1.0 M NH4Cl (Kb for ammonia = 1.76 x 10^-5)
Ka * Kb = 1*10^-14
Ka = 10^-14 / 1.76*10^-5
Ka = 5.68*10^-10
pH = -log( 5.68*10^-10) + log (1/1)
pH = -log( 5.68*10^-10)
pH = 9.25
The most effective buffer at pH 9.25 will be a mixture of 1.0 M NH3 and 1.0 M NH4Cl
the physical properties of ammonium sulphate are colorless gas, less dense than air, pungent shell, very soluble in water, alkaline gas
The answer is B. bases measure below seven
think of it like this 7 is neutral going down from seven it rises in acidity and going up from seven increases in alkalinity
