The correct answer is C) Raising the temperature increases reaction rate by increasing the energy of the reacting atoms/ions/molecules and increases the number of collisions.
Missing data in your question: (please check the attached photo)
from this balanced equation:
M(OH)2(s) ↔ M2+(aq) + 2OH-(aq) and when we have Ksp = 2x10^-16
∴Ksp = [M2+][OH]^2
2x10^-16 = [M2+][OH]^2
a) SO at PH = 7 ∴POH = 14-PH = 14- 7 = 7
when POH = -㏒[OH]
7= -㏒[OH]
∴[OH] = 1x10^-7 m by substitution with this value in the Ksp formula,
∴[M2+] =Ksp /[OH]^2
= (2x10^-16)/(1x10^-7)^2
= 0.02 M
b) at PH =10when POH = 14- PH = 14-10 = 4
when POH = -㏒[OH-]
4 = -㏒[OH-]
∴[OH] = 1x10^-4 ,by substitution with this value in the Ksp formula
[M2+] = Ksp/ [OH]^2
= 2x10^-16 / (1x10^-4)^2
= 2x10^-8 Mc) at PH= 14
when POH = 14-PH
= 14 - 14
= 0
when POH = -㏒[OH]
0 = - ㏒[OH]
∴[OH] = 1 m
by substitution with this value in Ksp formula :
[M2+] = Ksp / [OH]^2
= (2x10^-16) / 1^2
= 2x10^-16 M
Moles = mass / molar mass
molar mass of O2 is 32
therefore moles = 72/32
= 2.25 moles
For a closed system, you need two things:
1) a conservation of mass within the boundaries of the system
2) the ability to freely exchange energy to & from the "closed" system with a surrounding external system
So, the answer is <u><em>never</em></u>, since your defining the "system" as the water within the bathtub, and an open bathtub is exposed to evaporation, which is not conserving mass within the defined "system".
The number of moles of ethanol the chemist will use in the experiment involving 30g of ethanol is 0.65moles.
<h3>How to calculate number of moles?</h3>
The number of moles of a substance can be calculated by dividing the mass of the substance by its molar mass. That is;
no. of moles = mass ÷ molar mass
According to this question, a chemist will use a sample of 30 g of ethanol (CH3CH2OH) in an experiment. The number of moles can be calculated as follows:
Molar mass of ethanol = 12(2) + 1(5) + 17 = 46g/mol
no of moles = 30g ÷ 46g/mol
no. of moles = 0.65moles
Therefore, the number of moles of ethanol the chemist will use in the experiment involving 30g of ethanol is 0.65moles.
Learn more about moles at: brainly.com/question/1458253