I need help with the 14 and the 15

Fish breathe the dissolved air in water through their gills. Assuming the partial pressures of oxygen and nitrogen in air to be

amid [387]

Answer:

X(O₂) = 0.323

X(N₂) = 0.677

Explanation:

We have the partial pressures of oxygen (O₂) and nitrogen (N₂):

P(O₂) = 0.20 atm

P(N₂) = 0.80 atm

In order to solve the problem, you need the solubilities of each gas in water at 298 K. We can consider 1.3 x 10⁻³ mol/(L atm) for oxygen (O₂) and 6.8 x 10⁻⁴mol/(L atm) for nitrogen (N₂) from the bibliography.

s(O₂) = 1.3 x 10⁻³ mol/(L atm)

s(N₂) = 6.8 x 10⁻⁴mol/(L atm)

So, we calculate the concentration (C) of each gas as the product of its partial pressure (P) and the solubility (s):

C(O₂) = P(O₂) x s(O₂) = 0.20 atm x 1.3 x 10⁻³ mol/(L atm) = 2.6 x 10⁻⁴mol/L

C(N₂) = P(N₂) x s(N₂) = 0.80 atm x 6.8 x 10⁻⁴mol/(L atm) = 5.44 x 10⁻⁴ mol/L

In 1 liter of water, we have the following number of moles (n):

n(O₂) = 2.6 x 10⁻⁴ mol

n(N₂) = 5.44 x 10⁻⁴ mol

Thus, the total number of moles (nt) is calculated as the sum of the number of moles of the gases in the mixture:

nt = n(O₂) + n(N₂) = 2.6 x 10⁻⁴ mol + 5.44 x 10⁻⁴ mol = 8.04 x 10⁻⁴ mol

Finally, the mole fraction of each gas is calculated as the ratio between the number of moles of each gas and the total number of moles:

X(O₂) = n(O₂)/nt = 2.6 x 10⁻⁴ mol/(8.04 x 10⁻⁴ mol) = 0.323

X(N₂) = n(N₂)/nt = 5.44 x 10⁻⁴ mol/(8.04 x 10⁻⁴ mol) = 0.677

5 0

2 years ago

A solution containing equal numbers of hydrogen ions and hydroxide ions is

igor_vitrenko [27]

Answer:

The answer to your question is: Neutral

Explanation:

A neutral solution is a solution whose pH is 7.

That means that this solution has the same amount of H⁺ and OH⁻.

Examples of neutral solutions:

- distilled water

- sugar solution

- table salt

- cooking oil.

4 0

3 years ago

A dry mixture of KNO3 and sand could be separated by

Tatiana [17]

Place the mixture in hot water and stir well.
The KNO3 is very soluble in hot water. 
Use a fine filter paper and filter off the sand. 
The sand will be separated from the KNO3 solution. 
The water can now be evaporated from the solution by further, gentle heating leaving the solid in the container.

7 0

3 years ago

To plot the calibration curve, you need to prepare iron solutions with known concentrations and measure their absorbance.

kap26 [50]

To plot the calibration curve, you need to prepare iron solutions with known concentrations and measure their absorbance. You need to pipet 0 mL of the diluted solution to have 0.00 mg of iron.

In spectrophotometry, to plot the calibration curve, you need to prepare solutions with known concentrations and measure their absorbance.

We have a standard iron solution with a concentration of 0.2500g/L of pure iron (C₁). We pipet 25.00mL (V₁) of this standard iron solution into a 500mL (V₂) volumetric flask and dilute up to the mark with distilled water.

We can calculate the concentration of the diluted solution (C₂) using the dilution rule.

$C_1 \times V_1 = C_2 \times V_2\\\\C_2 = \frac{C_1 \times V_1}{V_2} = \frac{0.2500 g/L \times 25.00 mL}{500 mL} = 0.0125 g/L$

Then, if we wanted to prepare the blank, that is, the solution that contains the same matrix but not the analyte, and whose concentration in iron is 0.00 mg/L, we wouldn't pipet any of the diluted solution.

To plot the calibration curve, you need to prepare iron solutions with known concentrations and measure their absorbance. You need to pipet 0 mL of the diluted solution to have 0.00 mg of iron.

Learn more: brainly.com/question/24195565

8 0

2 years ago

Determine the unknown mineral using the information given below. Be sure to use significant figure rules when doing calculations

Mademuasel [1]

Answer:

Mass: 981.0 g

Density: 5.61 g/cm^3

Hardness: = 2.5 - 3

Unknown material: Chalcocite

8 0

3 years ago