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Sergeu [11.5K]
2 years ago
3

In one of the experiments we will use a spectrophotometer to determine the absorbance of ________________. In that same experime

nt the control will be a cuvette filled with _____________.
Chemistry
2 answers:
Maru [420]2 years ago
4 0

Answer:

The beam

A blank solution/solvent

Explanation:

Spectrophotometry is used to measure the amount of light that passes through a sample material and, by comparison to the initial intensity of light reaching the sample, they indirectly measure the amount of light absorbed by that sample

A blank is a sample that contains everything except for the analyte of interest. It is a sample of solvent. It is used for the calibration of the machine etc.

larisa [96]2 years ago
3 0

Answer:

Amount of photons, water

Explanation:

A spectrophotometer is a machine used to measure the absorption of light by a substance. A light beam is passed through the substance, and the light intensity is measured. A cuvette filled with water is called a blank, when a blank is measured it is used to calibrate the spectrophotometer reading.

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A group of students are wandering around a room. when their teacher claps, the students sit down wherever they are. this situati
Oksi-84 [34.3K]

an amorphous solid because the particles do not have a regular structure is the answer

8 0
2 years ago
Read 2 more answers
Draw a structure containing only carbon and hydrogen that is a stable alkyne of five carbons containing a ring.
stepladder [879]

Answer:

                     Ethynylcyclopropane is the stable isomer for given alkyne.

Explanation:

                     In order to solve this problem we will first calculate the number of Hydrogen atoms. The general formula for alkynes is as,

                                                    CₙH₂ₙ₋₂

Putting value on n = 5,

                                                    C₅H₂.₅₋₂

                                                    C₅H₈

Also, the statement states that the compound contains one ring therefore, we will subtract 2 hydrogen atoms from the above formula i.e.

                      C₅H₈   ------------(-2 H) ---------->  C₅H₆

Hence, the molecular formula for given compound is C₅H₆

Below, 4 different isomers with molecular formula C₅H₆ are attached.

                                      The first compound i.e. ethynylcyclopropane is stable. As we know that alkynes are sp hybridized. The angle between C-C-H in alkynes is 180°. Hence, in this structure it can be seen that the alkyne part is linear and also the cyclopropane part is a well known moiety.

                                      Compounds 3-ethylcycloprop-1-yne, <u>cyclopentyne </u>and 3-methylcyclobut-1-yne are highly unstable. The main reason for the instability is the presence of triple bond in three, five and four membered ring. As the alkynes are linear but the C-C-H bond in these compound is less than 180° which will make them highly unstable.

5 0
2 years ago
The amount of gas that occupies 36.52 L at 68.0°C and 672 mm Hg is __________ mol.
ASHA 777 [7]
We assume that this gas is an ideal gas. We use the ideal gas equation to calculate the amount of the gas in moles. It is expressed as:

PV = nRT
(672) (1/760) (36.52) = n (0.08206) ( 68 +273.15)
n = 1.15 mol of gas

Hope this answers the question. Have a nice day.
7 0
2 years ago
Q1) A vapor-compression refrigeration system operates on the cycle of Fig. 9.1. The refrigerant is 1,1,1,2-Tetrafluoroethane. Gi
hoa [83]

Answer:

i)   0.5071 (kg/s)

ii)  -1407.1 kj/kg

iii)  204.05 Kw

iv)  5.881

v)    9.238

Explanation:

Given Data:

evaporation temperature ( T ) = 4°c = 277.15 K

Condensation Temperature ( T ) = 34°c = 307.15 K

<em>n</em> ( compressor efficiency ) = 0.76

refrigeration rate = 1200 kJ.s^-1

i) determine the circulation rate of the refrigerant

m = \frac{Q}{H2 - H1}  = \frac{Q}{H2 - H4\\}  ------- 1

Q = 1200 Kj.s^-1

H2 = entropy at step 2 = 2508.9 (kJ / kg ) ( gotten from Table F )

H4 = entropy at step 4 = 142.4 ( kJ/ kg )

back to equation 1

m ( circulation rate of refrigerant ) = 0.5071 (kg/s)

ii) heat transfer rate in the condenser

Q = m ( H4 - H3 )

    = 0.5071 ( 142.4 - 2911.27 )

    = -1407.1 kj/kg

where H3 = H2 + ΔH23 = 2911.27 (kj/kg) ( as calculated )

iii) power requirement

w = m * ΔH23

   = 0.5071 (kg/s) * 402.37 (kj/kg) =  204.05 Kw

where: ΔH23 = \frac{H'3 - H2 }{0.76} = \frac{2814.7-2508.9}{0.76} = 402.37 (kj/kg)

iv) coefficient of performance of a cycle

W = Qc / w

  = 1200 Kj.s^-1/ 204.05 kw

  = 5.881

v) coefficient of performance of a Carnot refrigeration cycle

w_{carnot} = \frac{T2}{T4 - T2}

            =  277.15 / ( 307.15 - 277.15 )

            = 9.238

4 0
2 years ago
A sample from solution a and solution b were each tested with blue colored glucose indicator solution before the solutions were
vova2212 [387]
With the given problem you gave here, I can't answer the question because I need more details. Luckily, I found a similar problem that's provided with a diagram and a table shown in the attached picture.

This test is called the Benedict's test which is used as test for presence of sugars. If the solution contains sugar, like glucose, the solution would turn from blue to red. If not, it would stay blue. <em>Therefore, the correct results would be that in row 3.</em>

3 0
2 years ago
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