Answer is: molality od sodium chloride is 2,55 mol/kg.
V(solution) = 100 ml.
m(solution) = d(solution) · V(solution).
m(solution) = 1,10 g/ml · 100 ml.
m(solution) = 110 g.
ω(NaCl) = 13,0% = 0,13.
m(NaCl) = ω(NaCl) · m(solution).
m(NaCl) = 0,13 · 110 g.
m(NaCl) = 14,3 g.
n(NaCl) = m(NaCl) ÷ M(NaCl).
n(NaCl) = 14,3 g ÷ 58,5 g/mol.
n(NaCl) = 0,244 mol.
m(H₂O) = 110 g - 14,3 g.
m(H₂O) = 95,7 g = 0,0957 kg.
b(NaCl) = n(NaCl) ÷ m(H₂O).
b(NaCl) = 0,244 mol ÷ 0,0957 kg.
b(NaCl) = 2,55 mol/kg.
Answer:
Keiko should mix 20 mL 1% solution and 80 mL 6% solution for to make 100 mL 5% solution
Explanation:
There are 2 unknown values X= mL 6% solution and Y=1% solution. So, we need 2 equations:
1. Equation acid concentration. X mL 6% + Y mL 1% = 100 mL 5%
2. Equation solvent concentration X mL 94% + Y mL 99% = 100 mL 95%
When clearing X and Y :
(X mL 6% + Y mL 1% = 100 mL 5%) (-15,7)
X mL 94% + Y mL 99% = 100 mL 95%
_______________________________
- Y 0.83 = 16.5
Y = 19.9 mL 1% solution
Replace Y in anyone equation and X = 80 mL 6% solution
I hope to see been helpful
Let's evaluate each choice. For the first choice, this is correct. Hydrosphere consist of all the water's in the Earth's surface. It interacts with the atmosphere through reaeration, so that water cycle continues on. The second option is correct, this is known as the greenhouse effect. The third option is incorrect, because the opposite is true, which makes the fourth option correct. The fifth option is incorrect because the atmosphere has nothing to do with the Earth's crust. <em>So, the answers are: A, B, and D.</em>
