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noname [10]
3 years ago
8

When testing water for chemical impurities, results are often reported as BDL, that is, below detection limit. The following are

the measurements of the amount of blood in a series of water samples taken from inner - city households (in parts per million):
5, 7, 12, bdl, 10, 8, bdl, 20, 6
Chemistry
1 answer:
Mumz [18]3 years ago
4 0

Answer:

The median level in the water is 7ppm

Explanation:

LoB is assessed by calculating duplicates of a blank sample and evaluating the mean result and the standard deviation (SD). After evaluating this value LOD can be evaluated conferring to LOD=LOB+1.645(SD low concentration sample ). The quantitation limit can also be got from accuracy studies. LOD's may also be evaluated based on the standard deviation of the response (Sy) of the curve and the slope of the calibration curve (S) at levels resembling the LOD according to the formula: LOD = 3.3\frac{Sy}{S}

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Which elements on the periodic table fulfill the octet rule​
horsena [70]

Answer:

Noble Gases

Explanation:

The Noble Gases have a full valence shell of 8 electrons. They are stable in that sense.

8 0
3 years ago
PLEASE HELP ME ASAP!!! <br> I need the answer to #9. If you can show work please do.
scoundrel [369]

The correct answer would be 32/16s


7 0
3 years ago
What types of chemical<br> reactions can change a toxic<br> chemical into one that is less<br> toxic
Masteriza [31]

Answer:

Very toxic materials are substances that may cause significant harm or even death to an individual if even very small amounts enter the body.There are a number of very toxic materials that may be used in workplaces. Some examples include carbon monoxide, hydrogen sulfide, chlorine and sodium cyanide

Explanation:

here are generally four types of toxic entities; chemical, biological, physical and radiation: Chemical toxicants include inorganic substances such as, lead, mercury, hydrofluoric acid, and chlorine gas, and organic compounds such as methyl alcohol, most medications, and toxins.

8 0
3 years ago
How much energy (kJ) is required to change 0.18 mole of ice (s) at 0 C to water (l) at 0 C?
Dmitriy789 [7]

Answer:25,06 kJ of energy must be added to a 75 g block of ice.

ΔHfusion(H₂O) = 6,01 kJ/mol.

T(H₂O) = 0°C.

m(H₂O) = 75 g.

n(H₂O) = m(H₂O) ÷ M(H₂O).

n(H₂O) = 75 g ÷ 18 g/mol.

n(H₂O) = 4,17 mol.

Q = ΔHfusion(H₂O) · n(H₂O)

Q = 6,01 kJ/mol · 4,17 mol

Q = 25,06 kJ.

Explanation:

6 0
2 years ago
A student is trying to develop a model of an instant heat pack. What is the essential characteristic of the chemical reaction th
Lana71 [14]

The standard enthalpy of reaction should be negative.

<h3>What is enthalpy?</h3>

A thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.

Inside the heat pack are two chemicals that get mixed when you smush them together. As they mix, some weak bonds are broken, which takes a little bit of energy. But new, stronger bonds form which release energy. Releasing that energy causes the surroundings to heat up.

Hence, option B is correct.

Learn more about enthalpy here:

brainly.com/question/13775366

#SPJ1

3 0
2 years ago
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