Posted by Tichele on Saturday, December 11, 2010 at 9:53pm.
A 3.23 gram sample of a sodium bicarbonate mixture was reacted with excess acid. 48.52 mL of the evolved gas was collected over water at 0.930 arm and 23.0 degrees Celsius. What is the percentage of sodium bicarbonate in the original mixture?
The pressure of water at 23.0 degrees Celsius is 0.028 atm
Again, any help would be greatly appreciated!
- Chemistry - DrBob222, Saturday, December 11, 2010 at 10:57pm
Use PV = nRT and solve for n using the conditions in the problem. P that you substitute (in atm) is 0.930-(23.0/760) to correct for the fact it is collected over water and isn't dry. Then convert moles CO2 to moles NaHCO3 to grams NaHCO3 to percent NaHCO3.
- Chemistry - Tichele, Sunday, December 12, 2010 at 9:30am
This might be a stupid question, but why do I convert to moles of CO2 first?
- Chemistry - Tichele, Sunday, December 12, 2010 at 10:27am
Ok, so I've worked out the problem but I'm getting something like 6.6 x 10^-4 percent. That can't be right, can it?
Here's my work:
NaHCO3(s) + HCl(aq) ---> NaCl(aq) + CO2(g) + H2O(l)
Pressure of the gas= pressure of atmosphere - pressure of 23.0 degrees Celsius (found from table in my chem book) this comes out to .930atm-0.0277atm= 0.902atm
moles of CO2:
n=PV/RT= (.902atm x (48.53 x 10^-3 mL))/ (.08206 x 296)= 0.00180 moles CO2
Moles of NaHCO3:
0.00180mol CO2 x 1 mol NaHCO3/ 1 mol CO2= 0.00180 moles NaHCO3
Mass of NaHCO3:
0.00180mol/84 grams= 2.143 x 10^-5 g NaHCO3
Percent= (2.143x 10^-5) / 3.32 grams all multiplied by 100
Here is where I'm getting that 6.6 something x 10^-4 or something percent. Is that even possible???
Answer This Question
More Related Questions
- Chemistry - A 3.23 gram sample of a sodium bicarbonate mixture was reacted with ...
- AP Chemistry - A mixture of aluminum and zinc metal is used in 2 experiments ...
- Chemistry - A 0.0677g sample of magnesium metal reacted with excess hydrochloric...
- chemistry 30a - What volume (in mL) of an 8% w/v acetic acid solution would be ...
- AP Chem - a 4.22 gram sample of copper II sulfide was added to excess ...
- chem - At hihg temperatures Sodium chlorate decomposes to form Sodium Chloride ...
- chemistry - A sample of hydrogen gas was collected over water at 36 degrees ...
- Chemistry - A 40.0 g sample of zinc is allowed to react with excess hydrochloric...
- Chemistry - A 0.188g sample of unknown metal, X (s), produced 71.4 ml of ...
- chemistry - a 500ml sample of o2 gas at 24 degrees celsius was prepared by ...