Molarity

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$M = \frac {Mol Solute} {LiterSolution}$

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Examples

How many grams of NaCl are in 100. mL of $0.45M$ NaCl

$$ 100mL * \frac {1L} {1000mL} * \frac {0.45molNaCl} {1L} * \frac {58.44g} {1mol} = 2.6g NaCl $$

If you have $3.0M$ $Zn(NO_3)_2$ , What concentration of $NO_3^-$

$$ 3.0molZn(NO_3)_2 * \frac {2molNO_3^-} {1molZn(NO_3)2} = 6.0M{~~} NO_3 $$

If $100mL$ of $2.0M$ of HCL react with $3.0M$ NaOH, what volume NaOH fully react

$$ HCl + NaOH_{~~~~} -> NaCl + H_2O $$

$$ 100mL_~HCl * \frac {1L} {1000mL} * \frac {2mol_~ HCl} {1L} * \frac {1mol_~ NaOH} {1mol_~ HCl} * \frac {1L} {3mol_~HCl} = 0.067L_~ NaOH $$

This is how I did the equation above: 100mL_~HCl * \\frac {1L} {1000mL} * \\frac {2mol_~ HCl} {1L} * \\frac {1mol_~ NaOH} {1mol_~ HCl} * \\frac {1L} {3mol_~HCl} = 0.067L_~ NaOH

If 100mL 2.0M HCL react with 100mL of 3.0M NaOH & the temperature increases from $20^oC$ to $40^oC$, what is the $\Delta H_{rxn}$? Assume: $d_{soln} = 1.1_~ \frac g {mol}$ & $C_{soln} = 4.2_~ \frac J {g*C^o}$