I messed up Èeeeeeeeeeeeeeeeeeeee

THIS HAS NOTHING TO DO WITH SCHOOL.

klio [65]

OMG yessss that is so cute she will totally accept

5 0

3 years ago

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What is the ph of a 0.20 M solution of NH4Cl? [Kb(NH3) = 1.8 x 10^-5]

Pavlova-9 [17]

"NH4+ <----> NH3 + H+

The constant of this equilibrium is: K = Kw / Kb = 1 x 10^-14 / 1.8 x 10^-5 =5.56 x 10^-10

5.56 x 10^-10 = x^2 / 0.20-x

x = [H+] =1.1 x 10^-5 M

pH = 5.0"

8 0

3 years ago

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4. DBearded waste of Co-60 must be stored until it is no longer radioactive. Cobalt-60

Bingel [31]

464 g radioisotope was present when the sample was put in storage

<h3>Further explanation</h3>

Given

Sample waste of Co-60 = 14.5 g

26.5 years in storage

Required

Initial sample

Solution

General formulas used in decay:

$\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}$

t = duration of decay

t 1/2 = half-life

N₀ = the number of initial radioactive atoms

Nt = the number of radioactive atoms left after decaying during T time

Half-life of Co-60 = 5.3 years

Input the value :

$\tt 14.5=No.\dfrac{1}{2}^{26.5/5.3}\\\\14.5=No.\dfrac{1}{2}^5\\\\No=\boxed{\bold{464~g}}$

8 0

2 years ago

Question 2(Multiple Choice Worth 4 points) (01.01 MC) Dominic and Eva are using the same type of stopwatches to measure the time

LekaFEV [45]

The results of Dominic and Eva's experiment is unreliable and can lead to a pseudoscientific claim primarily because they did not repeat their tests multiple times. Although, they used the same type of stopwatch in recording the time it takes for the chemical reaction to occur, they have different reactions times. Thus, it would have been better if they conducted several trials then obtained the average of their results.

6 0

3 years ago

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Farmers who raise cotton once used arsenic acid, H₃AsO₄, as a defoliant at harvest time. Arsenic acid is a polyprotic acid with

Stels [109]

Explanation:

The reaction equation will be as follows.

$H_{3}AsO_{4} \rightleftharpoons H_{2}AsO^{-}_{4} + H^{+}$