An 8 Molar (aqueous) solution contains H2O and HNO3. The solution has an S.G. of 1.24 at 25oC. HNO3 is a strong acid that completely dissociates in water.
a) Calculate the mass of I Litre of solution.
b) Calculate the mass concentration (g/L) of HNO3 in solution.
c) Calculate the mass fraction of HNO3 in solution.
d) Write the ion dissociation reaction equation.
e) Calculate the concentration of pH of the solution.
This is pretty straight forward. do you have any questions on how to do it?
a) To calculate the mass of 1 litre of solution, you need to know the density of the solution. The specific gravity (S.G.) given is 1.24, which is the ratio of the density of the solution to the density of pure water at 4 degrees Celsius.
To calculate the mass, we can use the formula:
mass = volume * density
Since the volume is given as 1 litre and the density of pure water at 4 degrees Celsius is 1000 g/L, we can calculate the mass as follows:
mass = 1 L * 1000 g/L * 1.24 = 1240 grams
Therefore, the mass of 1 litre of solution is 1240 grams.
b) To calculate the mass concentration (g/L) of HNO3 in solution, you need to know the molar mass of HNO3 and the molarity of the solution.
The molar mass of HNO3 is calculated as follows:
Atomic mass of hydrogen (H) = 1.01 g/mol
Atomic mass of nitrogen (N) = 14.01 g/mol
Atomic mass of oxygen (O) = 16.00 g/mol (x3) = 48.00 g/mol
Therefore, the molar mass of HNO3 is:
molar mass of HNO3 = (1.01 g/mol) + (14.01 g/mol) + (48.00 g/mol) = 63.02 g/mol
The molarity is given as 8 M (8 moles of HNO3 in 1 liter of solution). Therefore, the mass concentration of HNO3 in solution is:
mass concentration = molarity * molar mass = 8 M * 63.02 g/mol = 504.16 g/L
Therefore, the mass concentration of HNO3 in solution is 504.16 g/L.
c) To calculate the mass fraction of HNO3 in solution, you need to know the mass of HNO3 and the total mass of the solution.
We already calculated the mass of the solution in part a) as 1240 grams.
The mass of HNO3 can be calculated using the mass concentration and the volume:
mass of HNO3 = mass concentration * volume = 504.16 g/L * 1 L = 504.16 grams
Therefore, the mass fraction of HNO3 in the solution is:
mass fraction of HNO3 = mass of HNO3 / mass of solution = 504.16 g / 1240 g = 0.4065 (or 40.65%)
Therefore, the mass fraction of HNO3 in the solution is 40.65%.
d) The ion dissociation reaction equation for HNO3 is:
HNO3 + H2O ⇌ H3O+ + NO3-
In this reaction, HNO3 dissociates into H3O+ (hydronium ion) and NO3- (nitrate ion) in water.
e) The pH of a solution can be calculated using the concentration of hydronium ions (H3O+). Since HNO3 is a strong acid that completely dissociates in water, the concentration of H3O+ ions will be equal to the molarity of the solution.
Therefore, the concentration of hydronium ions (H3O+) in the solution is 8 M.
To calculate the pH of the solution, you can use the formula:
pH = -log[H3O+]
For the given concentration of H3O+ (8 M):
pH = -log(8) = -0.9031
Therefore, the pH of the solution is approximately 0.9031.
a) To calculate the mass of 1 liter of the solution, we need to know the density of the solution. The specific gravity (S.G.) of the solution is given as 1.24, which is the ratio of the density of the solution to the density of water. Since the density of water at 25°C is approximately 1 g/mL, the density of the solution can be calculated as follows:
Density of Solution = S.G. × Density of Water
Density of Solution = 1.24 × 1 g/mL
Density of Solution = 1.24 g/mL
Since the volume of the solution is given as 1 liter, which is equivalent to 1000 mL, the mass of 1 liter of the solution can be calculated using the density:
Mass of Solution = Density of Solution × Volume of Solution
Mass of Solution = 1.24 g/mL × 1000 mL
Mass of Solution = 1240 grams
Therefore, the mass of 1 liter of the solution is 1240 grams.
b) To calculate the mass concentration (g/L) of HNO3 in the solution, we need to know the molar mass of HNO3 and the molarity of the solution.
The molar mass of HNO3 can be calculated as follows:
H = 1.008 g/mol
N = 14.007 g/mol
O = 16.00 g/mol x 3 (since there are three oxygen atoms in HNO3)
Molar mass of HNO3 = 1.008 + 14.007 + 48.00 = 63.015 g/mol
To calculate the mass concentration (g/L) of HNO3, we multiply the molarity by the molar mass of HNO3:
Mass Concentration of HNO3 = Molarity of Solution × Molar Mass of HNO3
Mass Concentration of HNO3 = 8 M × 63.015 g/mol
Mass Concentration of HNO3 = 504.12 g/L
Therefore, the mass concentration of HNO3 in the solution is 504.12 g/L.
c) The mass fraction of HNO3 in the solution can be calculated by dividing the mass of HNO3 by the total mass of the solution.
To calculate the mass of HNO3, we multiply the mass concentration by the volume of the solution:
Mass of HNO3 = Mass Concentration of HNO3 × Volume of Solution
Mass of HNO3 = 504.12 g/L × 1 L
Mass of HNO3 = 504.12 grams
To calculate the total mass of the solution, we use the mass of 1 liter of the solution calculated in part (a):
Total Mass of Solution = Mass of Solution = 1240 grams
Finally, the mass fraction of HNO3 can be calculated as follows:
Mass Fraction of HNO3 = (Mass of HNO3 / Total Mass of Solution) × 100%
Mass Fraction of HNO3 = (504.12 g / 1240 g) × 100%
Mass Fraction of HNO3 = 40.55%
Therefore, the mass fraction of HNO3 in the solution is approximately 40.55%.
d) The ion dissociation reaction equation for HNO3 in water can be written as follows:
HNO3(aq) → H+(aq) + NO3-(aq)
HNO3 dissociates completely in water, forming H+ ions and NO3- ions.
e) To calculate the pH of the solution, we need to know the concentration of H+ ions in the solution. Since the HNO3 in the solution is an 8 Molar solution, the concentration of H+ ions is also 8 M.
pH is defined as the negative logarithm of the concentration of H+ ions:
pH = -log[H+]
Therefore, to calculate the pH of the solution, we take the negative logarithm of the concentration of H+ ions:
pH = -log(8) = -3
Therefore, the concentration of pH of the solution is 3.