To prepare a solution of NaBr, you weigh out 2.639 (±0.003) g and dissolve it to...

To prepare a solution of NaBr, you weigh out 2.639 (±0.003) g and dissolve it to specification in a volumetric flask whose volume is 100.00 (±0.08) mL. Express the molarity of the solution, along with its uncertainty, with an appropriate number of digits.

Expert Solution

Molar mass of NaBr = 102.894 g/mol
mass = 2.639 (±0.003) g

number of moles of NaBr, n= mass / molar mass
= {2.639 (±0.003)}/102.894
=0.02565 ± 0.00003

Volume,V = 100.00 (±0.08) mL = 0.10000 (±0.00008) L

M = n/V
= 0.02565 /10000
= 0.2565

To find uncertainty use:
delta M /M = delta n/ n + delta V / V
delta M / 0.2565 =0.00003/ 0.02565 + 0.00008/0.10000
delta M / 0.2565 = 0.001 + 0.0008
delta M / 0.2565 = 0.002
delta M = 0.0005

Answer: 0.2565 ± 0.0005

queen_honey_blossom answered 2 years ago

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