Calculate the concentration of F− in solution and its absolute uncertainty.

Question

A solution of F− is prepared by dissolving 0.0858 ± 0.0006 g NaF (molar mass = 41.989±0.001 g/mol ) in 155.00 ± 0.06 mL of water. Calculate the concentration of F− in solution and its absolute uncertainty.

Significant figures are graded for this problem. To avoid rounding errors, do not round your answers until the very end of your calculations.

[F−]=____ M

± =_____ M

Answer 1

molar mass NaF = 41.989 ± 0.001 g/mol

[NaF] = 0.0858 g x 1 mol/41.989 g / 0.15500 L = 0.013183 M

Absolute uncertainty (u) = [sqrt (0.0006/0.0858)² + (0.001/41.989)² + (0.06/155)²] * (0.0858/41.989 x 155) = do the math to find absolute uncertainty