Question

please help on all questions in the pics...

numbers: b, c, d, e, f

3. A student collected the following data in the laboratory. mass of flask, g 52.87 mass of flask and sample, g 53.42 concentration of NaOH solution, M 0.101 initial buret reading, mL 23.78 final buret reading, mL

Answer 1

Given that

Mass of sample = 53.42 g -52.87 g= 0.55 g

Volume = 23.78 -0.50= 23.28 ml

23.28 mL= 0.02328 L NaOH

Number of mole = moalrity * volume in L

n= 0.02328 L * 0.101 mol/L

= 0.00235 mol (NaOH)

The balance chemical equation of the reaction is as follows:

C₆H₈O₆ + 2 NaOH -----------> C₆H₆O₄Na₂ + 2 H₂O

Then the number of moles of ascorbic acid that reacted with 0.00235 mol of NaOH = 0.00235 /2= 0.001175 mol ,

molar mass of ascorbic acid = 176.09 g/mol.

Amount in g = number of moles * molar mass

m= 176.09 g/mol * 0.001175 mol = 0.207 g.

sample mass = 0.55g,

percentage of acid is = mass of ascorbic acid / sample mass*100

= 0.207 /0.55 *100 = 37.6%.