Which device converts the kinetic energy of water into mechanical energy?
2 answers:
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Answer:
97.1%
Explanation:
Using the ideal gas equation, the number of moles of hydrogen gas produced can be calculated from information provided about the volume of gas evolved at a given temperature and pressure.
The stoichiometry of the reaction is now used to obtain the number of moles of Zn that will produce a given number of moles of hydrogen from the balanced reaction equation as shown. This gives us the number of moles of zinc reacted hence the mass of zinc in the coin since it is assumed that all the zinc reacts.
This is now used to calculate the mass percentage of Zn as shown.
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.