Answer:
a) the atomic number is 15
b) the mass number is 15+16 = 31
c) element is phosphorus
d)Group 15 period 3
- The mass percent of
Pentane in solution is 16.49%
- The mass percent of
Hexane in solution is 83.51%
<u>Explanation</u>:
- Take 1 kg basis for the vapor: 35.5 mass% pentane = 355 g pentane with 645 g hexane.
-
Convert these values to mol% using their molecular weights:
Pentane: Mp = 72.15 g/mol -> 355g/72.15 g/mol = 4.92mol
Hexane: Mh = 86.18 g/mol -> 645g/86.18 g/mol = 7.48mol
Pentane mol%: yp = 4.92/(4.92+7.48) = 39.68%
Hexane mol%: yh = 100 - 39.68 = 60.32%
Pp-vap = 425 torr = 0.555atm
Ph-vap = 151 torr = 0.199atm
-
From Raoult's law we know:
Pp = xp Pp - vap = yp Pt (1)
Ph = xh Ph - vap = yh Pt (2)
-
Since it is a binary mixture we can write xh = (1 - xp) and yh = (1 - yp), therefore (2) becomes:
(1 - xp) Ph - vap = (1 - yp) Pt (3)
-
Substituting (1) into (3) we get:
(1-xp) Ph - vap = (1 - yp) xp Pp - vap / yp (4)
xp = Ph - vap / (Pp - vap/yp - Pp - vap + Ph - vap) (5)
-
Subbing in the values we find:
Pentane mol% in solution: xp = 19.08%
Hexane mol% in solution: xh = 80.92%
-
Now for converting these mol% to mass%, take 1 mol basis for the solution and multiplying it by molar mass:
mp = 0.1908 mol 72.15 g/mol
= 13.766 g
mh = 0.8092 mol 86.18 g/mol
= 69.737 g
-
Mass% of Pentane solution = 13.766/(13.766+69.737)
= 16.49%
-
Mass% of Hexane solution = 83.51%
Answer:
[H⁺] = 3.98×10⁻⁷ M
Explanation:
Given data:
pH of blood = 6.40
Hydrogen ion concentration = ?
Solution:
Formula:
pH = - log[H⁺]
by rearranging this formula,
[H⁺] = 10⁻(pH)
By putting values,
[H⁺] = 10 ⁻⁶°⁴⁰
[H⁺] = 3.98×10⁻⁷ M
Answer:
0.2 M
Explanation:
Step 1: Given data
- Mass of sugar (sucrose): 15 g
- Volume of water: 0.2 L (we will assume it is the volume of the solution)
There are different ways to express the concentration of a solution. We will calculate molarity, which is one of the most used.
Step 2: Calculate the moles of sucrose
The molar mass of sucrose is 342.3 g/mol.
15 g × 1 mol/342.3 g = 0.044 mol
Step 3: Calculate the molarity of the solution
Molarity is equal to the moles of solute divided by the liters of solution.
M = 0.044 mol/0.2 L = 0.2 M