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sveticcg [70]
3 years ago
15

Sewage and industrial pollutants dumped into a body of water can reduce the dissolved oxygen concentration and adversely affect

aquatic species. In one study, weekly readings are taken from the same location in a river over a two-month period. The week 3 measurement in the data set is suspected of being an outlier.
True or False: According to the Q test, the value at week 3 can be rejected at the 95% confidence level.
Week Dissolved O2 (ppm)
1 4.9
2 5.1
3 5.6
4 4.3
5 4.7
6 4.9
7 4.5
8 5.1
Chemistry
1 answer:
MArishka [77]3 years ago
7 0

Answer:

FALSE

Since 0.385 < 0.526, the value for week 3 is accepted.

Explanation:

Qexp = (|Xq - Xₙ₋₁|)/w

where Xq is the suspected outlier; Xₙ₋₁ is the next nearest data point; w is the range of data

First, the data are arranged in decreasing order, from highest to lowest:

3. 5.6

2. 5.1

8. 5.1

1. 4.9

6. 4.9

5. 4.7

7. 4.5

4. 4.3

Xq = 5.6; Xₙ₋₁ = 5.1; w = 5.6 - 4.3 = 1.3

Qexp = (|5.6 - 5.1|)/1.3 = 0.385

From tables, at 95% confidence level, for n = 8, Qcrit = 0.526

Since 0.385 < 0.526, the value for week 3 is accepted.

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OlgaM077 [116]
Below are the steps to get the answers:

<span>1.) write out the balance equation 3NaOh+H3PO4->Na3PO4+3H2O
 
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3.) equation is deltaHneutraliztion=q/Moles of limiting reagent H3PO4 is limiting reagent because lowest moles, and is used up first
 
4.) Now plug in variables DeltaH=2.2*10^2(1.5*10^3)= 146.67kj/mole Notice we had to convert J to kj, </span>
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Water is believed to be one of the best fire extinguishers then why it is so that fire in oil spills over ocean/sea is difficult
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Answer:

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Explanation:

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6 0
3 years ago
Complete the table to summarize the properties of the different subatomic particles. Type in your answers.
Aloiza [94]

<h2>Complete the table to summarize the properties of the different subatomic particles. </h2>

Explanation:

Atom

It is a smallest particle which cant exist independently.

According To Dalton, atom was indivisible but later on, it was proved that atom can be subdivided into sub atomic particles called electron, proton & neutron.

These subatomic particles have marked properties .

Proton

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4 0
3 years ago
Read 2 more answers
A buffer solution contains 0.479 M NaHCO3 and 0.342 M Na2CO3. Determine the pH change when 0.091 mol HNO3 is added to 1.00 L of
pshichka [43]

Answer:

ΔpH = 0.20

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

There are 0.479moles of NaHCO₃ and 0.342moles of Na₂CO₃.

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.342mol / 0.479mol

<em>pH = 10.05</em>

NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:

NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺

0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.342mol + 0.091mol: 0.433mol

HCO₃⁻: 0.479mol - 0.091 mol: 0.388mol

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.433mol / 0.388mol

pH = 10.25

That means change of pH, ΔpH is:

ΔpH = 10.25 - 10.05 = <em>0.20</em>

<em />

I hope it helps!

3 0
3 years ago
What mass of silver nitrate will be needed to react with 125 grams of magnesium chloride?
Gennadij [26K]

Answer:   m =  4.2 gAgCl

Explanation:  

5 0
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