Question

Sa se calculeze cantitatea procentuala : a) adaugarea a 200g apa la 100g solutie 25% b) adaugarea a 5g sare de bucatarie la 75 g solutie sare de bucatarie cu concentratia 2%.

Answer 1

a. ms¹ = 100g

m apă = 200g

C¹=25%

Csf% = ?

C¹% = ( md / ms ) × 100

C¹% / 100 = md / ms

md = ( ms × C¹% ) / 100

md = ( 100 × 25 ) / 100

md = 25g

Csf% = ( md / msf ) × 100

msf = ms¹ + m apă

msf = 100g + 200g

msf = 300g

Csf% = ( 25 / 300 ) × 100

Csf% = 25 / 3

Csf% = 8,33 ( aproximativ )

b. ms¹ = 75g

Cs¹% = 2

md² = 5g

Csf% = ?

C¹% = ( md¹ / ms¹ ) × 100

C¹% / 100 = md¹ / ms¹

md¹ = ( ms¹ × C¹% ) / 100

md¹ = ( 75g × 2 ) / 100

md¹ = 1,5 g

Csf% = ( mdf / msf ) × 100

mdf = md¹ + md²

mdf = 1,5g + 5g

mdf = 6,5 g

msf = ms¹ + md²

msf = 75g + 5g

msf = 80g

Csf% = ( 6,5 / 80 ) × 100

Csf% = 65 / 8

Csf% = 8,125