Question

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)

_______________________________________

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

Answer 1

It looks right, but I can't be sure if you're entirely correct.
Did you use your textbook to find these values?

Answer 2

The solubilities of the of the compunds i found on the internet the rest from the textbook.

Answer 3

I love you man

Answer 4

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

Answer 5

Hey! thanks so much! Love you!