# Chemistry 101

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I don't remember my instructor going over this and the book isn't explaining it very well. Can anyone help answer these?

Indicate the concentration of each ion or molecule present in the following solutions.

1. 0.30 M NaNO3
2. 1.5x10^-2 M MgSO4
3. 2.00x10-2 M C6H12O6
4. A mixture of 45.0 mL of 0.272M NaCl and 65.0 mL of 0.0247M (NH4)2CO3. Assume that the volumes are additive.

Thank you for the help!

• Chemistry 101 -

1. 0.30 M NaNO3. You have 1 Na ion and 1 nitrate ion per molecule of NaNO3; therefore (Na^+) = (NO3^-) = 0.30 M.

2. You have 1 Mg ion and 1 sulfate ion per molecule of MgSO4; therefore, (Mg^+) = (SO4^-2) = 1.5 x 10^-2 M3.

3. C6H12O6 is an organic molecule; it doesn't ionize; therefore, the molecule concn is 2.00 x 10^-2 M.

4.You have diluted NaCl from 45.0 mL to 110 mL (45 mL + 65 mL = 110 mL) so the new concn NaCl is 0.272 M x (45.0/110.0) = ?? and that is the (Na^+) and (Cl^-).
Similarly, (NH4)2CO3 is
0.0247 M x (65.0/110.0) = ?? M.
?? M is the (CO3^-2) and 2 x ??M is the (NH4^+) (because there are two of them per molecule of (NH4)2CO3.

• Chemistry 101 -

8----D