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PolarNik [594]
3 years ago
5

Why was 1990 an important year regarding air quality?

Chemistry
2 answers:
DerKrebs [107]3 years ago
4 0

Answer:

100%

2 and 4

Explanation:

Valentin [98]3 years ago
3 0

Why was 1990 an important year regarding air quality? Check all that apply.

2.Cost-effective ways to reduce pollution were emphasized.


4.Modifications and improvements were made to the Clean Air Act.


i just took the test this is 100% correct

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A nuclear fission reaction has mass difference between the products and the reactants of 0.0284 amu. Calculate the
notsponge [240]

Answer:

C) 4.24 x 10^{-12}

Explanation:

E = Δmc^{2}

Δm = 0.0284 x 1.66 x 10^{-27} kg = 4.714x10^{-29}kg

putting value in above equation

E = 4.714x10^{-29}kg x (3x10^{8})^{2} = 4.24 x 10^{-12}

6 0
3 years ago
Why is it impossible to ever prove that a hypothesis is true?
maria [59]

Answer: A

Explanation:

Hypothesis have to be based on previous knowledge and have to be able to be tested but the problem is most hypothesis can’t be explained so it’s impossible to prove a hypothesis correct because science uses inductive reasoning

4 0
3 years ago
What is Delta.Gsystem for the system that is described by the following data? Delta.Hsystem = –345 kJ, T = 293 K, Delta.Ssystem
ryzh [129]

Answer:

-209 kJ

Explanation:

I did the math. You're welcome ;)

6 0
3 years ago
Consider an amphoteric hydroxide, m(oh)2(s), where m is a generic metal. estimate the solubility of m(oh)2 in a solution buffere
Colt1911 [192]
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 =10
when 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 M
c) 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


8 0
3 years ago
I need the answers to those 2 :) don’t explain just answer :D
Gwar [14]

Answer:

where is the question?

Explanation:

4 0
3 years ago
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