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Oksana_A [137]
3 years ago
8

Two 0.9mL aliquots of the same specimen are placed in test tubes. To one is added 0.1 mL of water (spec A). To the other is adde

d 0.1 mL of 200 mg/dl urea (spec B). They are analyzed for their results: Spec A: 25 mg/dl, Spec B: 43 mg/dl. What is the percent recovery of this method?
Chemistry
1 answer:
Tanya [424]3 years ago
8 0
We assume that the method that made use of urea was able to recover all of the recoverable substance. The method in question is the method that makes use of water.
The total amount of substance is 43 mg/dl. The recovered amount is 25 mg/dl. The percent recovery is
(25 mg/dl / 43 mg/dl) * 100 = 58.14%
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Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 15.4 u.
mixas84 [53]

Answer:

N, B, Be, C

Explanation:

N (Nitrogen) has 14.0067 B (Boron) has 10.81 Be (Beryllium) has 9 and C (Carbon) has 12

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2 years ago
Question 6 (4 points)
pishuonlain [190]

Answer:

20.9%

Explanation:

I took the test i hope this helps:)

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Read 2 more answers
Will bromine react with sodium and why?
Archy [21]

<span><span>When you write down the electronic configuration of bromine and sodium, you get this

Na:
Br: </span></span>

<span><span />So here we the know the valence electrons for each;</span>

<span><span>Na:  (2e)
Br:  (7e, you don't count for the d orbitals)

Then, once you know this, you can deduce how many bonds each can do and you discover that bromine can do one bond since he has one electron missing in his p orbital, but that weirdly, since the s orbital of sodium is full and thus, should not make any bond.

However, it is possible for sodium to come in an excited state in wich he will have sent one of its electrons on an higher shell to have this valence configuration:</span></span>

<span><span /></span><span><span>

</span>where here now it has two lonely valence electrons, one on the s and the other on the p, so that it can do a total of two bonds.</span><span>That's why bromine and sodium can form </span>

<span>
</span>

4 0
3 years ago
Chemistry acids and bases
Ket [755]

Answer:

Imma just say acids have more acidity and bases have lower acidity...

4 0
3 years ago
The The thermal conductivity of a sheet of rigid, extruded insulation is reported to be k=0.029 W/ m measured temperature differ
vfiekz [6]

Answer:

Heat flux = 13.92 W/m2

Rate of heat transfer throug the 3m x 3m sheet = 125.28 W

The thermal resistance of the 3x3m sheet is 0.0958 K/W

Explanation:

The rate of heat transfer through a 3m x 3m sheet of insulation can be calculated as:

q=-k*A*\frac{\Delta T}{\Delta X}\\\\q=-0.029\frac{W}{m*K}*(3m*3m)*\frac{12K}{0.025m}  =125.28W

The heat flux can be defined as the amount of heat flow by unit of area.

Using the previous calculation, we can estimate the heat flux:

heat \, flux=\frac{q}{A}=\frac{125.28 W}{9 m^{2} }  =13.92 W/m^{2}

It can also be calculated as:

q/A=-k*\frac{\Delta T}{\Delta X}

The thermal resistance can be expressed as

\Delta T=R_t*Q\\R_t=\Delta T/Q=\frac{\Delta X}{k*A}

For the 3m x 3m sheet, the thermal resistance is

R_t = \frac{\Delta X}{k*A}=\frac{0.025m}{0.029W/mK*9m^{2}}=0.0958 \, K/W

4 0
3 years ago
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