A mixture of helium, nitrogen and oxygen has a total pressure of 756 mmHg. The partial
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Answer:
b. 10 mL
Explanation:
First we <u>calculate the amount of H⁺ moles in the acid</u>:
- pH = -log [H⁺]
- [H⁺] =
- [H⁺] = 10⁻⁵ = 1x10⁻⁵M
100 mL ⇒ 100 / 1000 = 0.100 L
- 1x10⁻⁵M * 0.100 L = 1x10⁻⁶ mol H⁺
In order to have a neutral solution we would need the same amount of OH⁻ moles.
We can use the pOH value of the strong base:
- pOH = 14 - pH
- pOH = 14 - 10 = 4
Then we <u>calculate the molar concentration of the OH⁻ species in the basic solution</u>:
- pOH = -log [OH⁻]
- [OH⁻] =
= 1x10⁻⁴ M
If we use 10 mL of the basic solution the number of OH⁻ would be:
10 mL ⇒ 10 / 1000 = 0.010 L
- 1x10⁻⁴ M * 0.010 L = 1x10⁻⁶ mol OH⁻
It would be equal to the moles of H⁺ so the answer is b.
Answer: 126.1 grams of are needed to make 5.3 L of 0.25 M solution
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
To calculate the mass of solute for given molarity, we use the equation:
Thus 126.1 grams of are needed to make 5.3 L of 0.25 M solution