Hi, i actually posted this up before..please double check the answers if i got them right have to hand in on Wednesday:
The Chemicals are:
Baking Soda- NaHC03
Calcium Chloride- CaCl2
Bromothymol Blue - (acid base indicator)
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What is:
(a) The equations for the dissolution of calcium chloride and sodium bicarbonate in water
1. CaCl2(s)---> Ca^2+(aq)+ 2Cl^-(aq)
2. NaHCO3(s) ---> Na+(aq) + HCO3^-(aq)
(b) Look up the heats of solutions for calcium chloride and sodium bicarbonate ( indicate exothermic and endothermic reaction)
Calcium choride
= -795.8 kJ mol^-1
= exothermic
Sodium bicarbonate
= -950.8 kJ mol^-1
= exothermic
(c)Look up the solubilities of these two salts and any other salts that may form, in put in a Ziploc bag.
Solubilities in water:
CaCl2- 74.5 g/ 100ml ( 20C)
NaHCO3- 7.8 g/ 100ml (18C)
other salts that may form are:
1.NaCl- 35.9 g/ 100ml (25C)
2.Ca(OH)2- 0.185g/ 100 cm3
3.Ca(HCO3)2- 16.6 g/100ml ( 20C)
4.CaCO3- 0.00015 mol/l (25C)
And CO2 will form after the bicarbonate breaks down : 0.00145g/ml ( 25C)
(d)Write out the equations for the neutralization of a strong acid with a strong base.
1. HCl(aq)+NaOH(aq)---> NaCl(aq)+H20(l)
2. 2HBr(aq)+Ba(OH)2(aq)-->BaBr2(aq)+2H2O
3. HI (aq)+ NaOH--> NaI(aq) + H2O
4. 2HClO4+Sr(OH)2--> Sr(ClO4)2+ 2H20
(e)Write out the Ka and Kb for the biocarbonate ion with chemical equation
HCO3^-(aq) <--> H+(aq) + CO3^-2(aq)
Ka = [H+][CO3-2]/[HCO3-
H2O + CO3-2(aq) <--> HCO3-(aq) + OH-(aq)
Kb = [HCO3-][OH-]/[CO3-2]
(F) the pH range for the indicator bromothymol blue
The pH range for bromothymol blue is
= Y 6.0 - 7.0 B
It looks right, but I can't be sure if you're entirely correct.
Did you use your textbook to find these values?
The solubilities of the of the compunds i found on the internet the rest from the textbook.
I love you man
hey if u guys are still around, i think e is wrong. check general chem text book pg 682 table 16.4 it shows u the Ka equation for bicarbonate and even the ka value
Hey! thanks so much! Love you!
(a) The equations for the dissolution of calcium chloride and sodium bicarbonate in water are correct.
(b) The heats of solutions for calcium chloride and sodium bicarbonate you provided are correct. Calcium chloride has a heat of solution of -795.8 kJ mol^-1, indicating an exothermic reaction. Sodium bicarbonate also has a heat of solution of -950.8 kJ mol^-1, indicating an exothermic reaction.
(c) The solubilities you provided for calcium chloride and sodium bicarbonate are correct. The solubility of calcium chloride in water is 74.5 g/100ml at 20°C, and the solubility of sodium bicarbonate in water is 7.8 g/100ml at 18°C. The other salts that may form and their solubilities you provided are also correct.
(d) The equations you wrote for the neutralization of a strong acid with a strong base are correct. The reactions listed show the neutralization of various strong acids (HCl, HBr, HI, HClO4) with various strong bases (NaOH, Ba(OH)2, Sr(OH)2).
(e) The equations you wrote for the Ka and Kb of the bicarbonate ion are correct. Ka represents the acid dissociation constant, and Kb represents the base dissociation constant. The Ka equation shows the equilibrium between bicarbonate ion, hydrogen ion, and carbonate ion. The Kb equation shows the equilibrium between water, carbonate ion, bicarbonate ion, and hydroxide ion.
(f) The pH range for the indicator bromothymol blue is correct. Bromothymol blue changes color from yellow (acidic) to blue (basic) within the pH range of 6.0 to 7.0.