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chem help

A 0.6181 gram sample of M2CO3 was taken and dissolved in enough water to make 100.0 mL of solution A. A 10.00 mL aliquot of solution A was taken and 25.00 mL of 0.1842 M HCl added.

M2CO3(aq) + 2HCl(aq) 2MCl(aq) + H2O(l) + CO2(g)

It took 19.90 mL of 0.1473 M NaOH to titrate the resulting solution.

NaOH(aq) + HCl(aq) H2O(l) + NaCl(aq)

What is the metal, M?

Please give a clear step-by-step answer :smile:

thanks in advance!

Reply 1

tuxedo-

1. Calculate moles of NaOH titrated. (n=cv)

2. Work out therefore the moles of HCl reacted using the ratio in the reaction.

3. Calculate the moles of HCl added to the aliquot of solution A.

4. Subtract 2 from 3. (moles in 3 - moles in 2) This gives the moles of acid that reacted with M2CO3.

5. Using the ratio in the reaction, work out the moles of M2CO3 that reacted with this many moles of acid.

6. Multiply this by 10, to get moles of M2CO3 in the 100ml solution.

7. Work out the Mr of M2CO3 using the moles you calculated, and the mass given in the question (mr=mass/moles)

8. Subtract from the Mr, the Mr of CO3 to get the Mr of M2.

9. Divide that by 2, to get the Ar of M.

10. Look at the periodic table to find the element with the corresponding relative atomic mass.

Let me know if you have an answer to check.

Reply 2

Adamstuxent

Original post by tuxedo-

1. Calculate moles of NaOH titrated. (n=cv)
2. Work out therefore the moles of HCl reacted using the ratio in the reaction.
3. Calculate the moles of HCl added to the aliquot of solution A.
4. Subtract 2 from 3. (moles in 3 - moles in 2) This gives the moles of acid that reacted with M2CO3.
5. Using the ratio in the reaction, work out the moles of M2CO3 that reacted with this many moles of acid.
6. Multiply this by 10, to get moles of M2CO3 in the 100ml solution.
7. Work out the Mr of M2CO3 using the moles you calculated, and the mass given in the question (mr=mass/moles)
8. Subtract from the Mr, the Mr of CO3 to get the Mr of M2.
9. Divide that by 2, to get the Ar of M.
10. Look at the periodic table to find the element with the corresponding relative atomic mass.
Let me know if you have an answer to check.