College Chemistry
posted by Anonymous .
how do i calculate the moles of Na2CO3 present in the original 25.00mL aliquot of carbonate solution??
the tared mass of Na2CO3 is 1.5179g

the calciul content of person's urine was determined on two different days to be:
day1:
Average Ca(mg/L)=238
Number of measurements=4
day2
Average Ca:268
Number of measurements=5
The analytical method was used known to have a standard deviation of 14mg/L
based on many trials.are the two average above significantly different at 95% confidence level
I used t student test and ended up with t=0.1064
am I right?
thanks 
You don't provide enough information. I know you posted this recently and I told you the same thing. Assuming you have more data, you can use one of the following.
mols Na2CO3 = M x L if you know those values.
mols = grams/molar mass if you know those values. 
I may be reading the problem wrong but I think the problem is asking you to compare the two sets of values and see if there is a statistical difference at the 95% confidence level. Equations are available for that. The one I have is
X1X2 = +/ ts_{pooled}*sqrt(N1+N2/N1N2) and for t you pick that from the table using n1+n22 degrees of freedom. X1 and X2 are the two sets of AVERAGES. 
) At a certain temperature a 2.00 L flask initially contained only 0.600 mol PCl3(g) and 0.0175 mol PCl5(g). After the system had reached equilibrium, 0.00400 mol Cl2(g) was found in the flask. Gaseous PCl5(g) decomposes according to the equation
PCl5(g) ↔ PCl3(g) + Cl2(g)
Calculate the equilibrium concentration of all species and the value of K.
Respond to this Question
Similar Questions

Chemistry HELP!!!
Only one question, it would be greatly appreciated if you would help me Thanx In an experiment, Na2CO3(aq) was added to 25.0 mL of CaCl2(aq) solution until no more precipitate was formed. The mass of precipitate produced was 2.50 g. … 
Chemistry
a. How many moles of Na2Co3 were present in the 15mL sample? 
Chemistry
a. How many moles of Na2Co3 were present in the 15mL sample? 
Chemistry
0.7g of an unknown mixture of NaHCO3 and Na2CO3 is mixed with 3mL of 12M HCl.what is the mass of NaHCO3 and Na2CO3 in the mixture of NaHCO3 and Na2CO3? 
chemistry
Sodium carbonate reacts with nitric acid according to the following equation: Na2CO3+2HNO3>2NaNO3+CO2+H2O a. how many moles of Na2CO3 are required to produce 100.0 g of NaNO3? 
College Chemistry
calculate the moles of sulfuric acid that remained in the solution after reaction with the carbonate. the tared mass of carbonate is 1.5179g 
Chemistry
I have had this question in my homework, and honestly I got stuck in these questions. I managed to convert 5.3g of Na2CO3 into moles, but then I got stuck and do not know what to do next to solve the question. If anyone knows how to … 
Chemistry
a solution of HCL is approximately 0.1M and has to be standardized . 1.234g Na2CO3 are dissolved to make 100ml of solution. 20mL of this solution are titrated with the HCL solution, requiring 31.3mL for the second equivalence point. … 
Chemistry Lab
Number of moles of HCl and Na2CO3 (show calculations) when 0.015 g of Na2CO3. How can I calculate this problem if I am only given the 0.015 grams of Na2CO3? 
Chemistrytitrations
Question: An unknown mass of (NH4)2CO3 is mixed with 4g of NaOH and dissolved in 100cm3 of water,which results a clear solution.Gasses are removed by heating the final solution. 2 parts of 25cm3 of final solution is taken and one is …