Question

The Chemicals are:

Baking Soda- NaHC03
Calcium Chloride- CaCl2
Bromothymol Blue - (acid base indicator)

_______________________________________

What is:

(a) The equations for the dissolution of calcium chloride and sodium bicarbonate in water

(b) Look up the heats of solutions for calcium chloride and sodium bicarbonate ( indicate exothermic and endothermic reaction)

(c)Look up the solubilities of these two salts and any other salts that may form, in put in a Ziploc bag.

(d)Write out the equations for the neutralization of a strong acid with a strong base.

(e)Write out the Ka and Kb for the biocarbonate ion with chemical equation

(F) the pH range for the indicator bromothymol blue

Answer 1

(a) The equations for the dissolution of calcium chloride and sodium bicarbonate in water
<b>CaCl2 ==> Ca^+2(aq) + 2Cl^=(aq)</b>

(b) Look up the heats of solutions for calcium chloride and sodium bicarbonate ( indicate exothermic and endothermic reaction)
<b>You can look up the heats of solution. It is an exothermic (heat is given off) solution if delta H is negative; endothermic (heat is absorbed)if delta H is positive.</b>

(c)Look up the solubilities of these two salts and any other salts that may form, in put in a Ziploc bag.
<b>You can look up the solubilities of CaCl2 and NaHCO3. What other salts may form? Look at double displacement type reactions and you will see that you can get CaCO3 and NaCl as well as Ca(HCO3)2</b>


(d)Write out the equations for the neutralization of a strong acid with a strong base.
<b>strong acid + strong base ==> salt + water. You can make up your own equation from your knowledge of strong acids and strong bases. HCl is a good example of a strong acid. NaOH(lye) is an example of a strong base. </b>

(e)Write out the Ka and Kb for the biocarbonate ion with chemical equation
<b>Note the correct spelling of bicarbonate. I assume this is just a typo.
HCO3^- ==> H^+ + CO3^-2 is the second ionization for H2CO3 (the first is the formatin of the HCO3^- ion). Can you write the Ka for the reaction I show? Kb is the hydrolysis equation for HCO3^-.
HCO3^- + HOH ==> H2CO3 + OH^-
Can you write Kb from that equation?</b>

(F) the pH range for the indicator bromothymol blue
<b>Use your text or the Internet to look up the pH range for bromthymol blue</b>

Answer 2

(a) I will give you one of these two:
NaHCO3(s) ---> Na+(aq) + HCO3-(aq)
(b) If you are asked that question, you must have access to printed materials that give the answers.
(c) Same as above answer.
(d) HCl + NaOH ---> NaCl + H2O
(several other possible examples using KOH, HNO3, LiOH, H2SO4, etc.)
(e) 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) Check here:
http://depts.uwc.edu/chemistry/helpful_files/indicators.html

Answer 3

<b>Note the typo I made in the dissolution of CaCl2
It should be CaCl2 ==>Ca^+2 + 2Cl^-

I didn't write the one for NaCl.
NaCl ==> Na^+ + Cl^-</b>

Answer 4

GK, why don't you write the concentration of water for (e)?

Answer 5

hey i think e is wrong. check pg 682 on ur text book. it actually shows u the equation on the table 16.4

Answer 6

(a) Nah

Answer 7

eric is right. pg 682 has it listed. but its the same thing gk was saying, just less work