Question

how many grams of water in 500. g of a 0.100 % m/m nacl solution ?
1 g nacl
(500. g soln)(-------------) = 2 g nacl
3 g soln
the grams of water = 4 g solution - 5 g nacl = 6 g
a. 36.00 b. 5.00 c. 31.00 d. 150.0 e. 12 f. 350.00
g. 100.0 h. 2.4 x 10^-2 i. 1.2 x 10^-3 j. 1.786 k. 7.143 l. 25.00
m. 7.500 n. 125.0 o. 500.0 p. 15.00 q. 185.00 r. 444.44
s. 2.00 x 10^3 t. 20.67 u. 0.500 v. 499.5 w. 15 x. 33.33
y. 1.00 x 10^5 z. 10.0 aa. 1.00 bb. 10^6 cc. 6.00
dd. 6.00 x 10^-5 ee. 6.00 x 10^6 ff. 20.0 gg. 200 hh. 1.20 x 10^6
ii. 60 jj. 0.100 kk. 4.00 ll. 10^3 mm. 0.0667 nn. 66.7

Explanation:

Step1: Calculate the mass of NaCl

The mass - by - mass percentage formula is \(\text{mass}\%=\frac{\text{mass of solute}}{\text{mass of solution}}\times100\). Given \(\text{mass}\% = 0.100\%\) and \(\text{mass of solution}=500\space g\). Rearranging for the mass of solute (\(m_{NaCl}\)) gives \(m_{NaCl}=\frac{\text{mass}\%}{100}\times\text{mass of solution}\). So, \(\frac{0.100}{100}\times500 = 0.500\space g\) (so \(1 = 0.100\), \(2 = 0.500\), \(3 = 100\)).

Step2: Calculate the mass of water

The mass of water \(m_{H_2O}=\text{mass of solution}-\text{mass of solute}\). The mass of solution is \(500\space g\) (so \(4 = 500.0\)) and the mass of solute (\(NaCl\)) is \(0.500\space g\) (so \(5 = 0.500\)). Then \(m_{H_2O}=500 - 0.500=499.5\space g\) (so \(6 = 499.5\)).

Answer:

1. JJ. \(0.100\)
2. U. \(0.500\)
3. AA. \(100\)
4. O. \(500.0\)
5. U. \(0.500\)
6. V. \(499.5\)