40 watts because 120-80 is forty or 80 + 40 - 120
Spectrophotometric cell or a cuvette is made of quartz for UV spectrophotometers. These cuvettes are used as sample holders for the spectrophotometric determination of the analytes. The material that makes up the cuvette and the condition of the cuvette is to be taken care of in order to avoid erroneous absorbance readings. The sample holder or the cuvette must be removed from the spectrophotometer in between two successive readings. This is to ensure that the light sensing detector of the instrument is not affected.
Answer:

Explanation:
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In this case, according to the given information it turns out possible for us to realize that one mole of the given compound, Mg(ClO₄)₂, has one mole of Mg, two moles of Cl and eight moles of O; thus, we proceed as follows:

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Answer: mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Explanation:
From the calculations, the heat of fusion of the substance is 0.73 kJ
<h3>What is is the heat of freezing?</h3>
The heat of freezing is the energy released when the substance is converted from liquid to solid.
Now we know that the molar mass of the substance is 82.9 g/mol hence the number of moles of the substance is; 13.3 g /82.9 g/mol = 0.16 moles
Now the heat of fusion shall be;
H = 4.60 kj/mol * 0.16 moles
H = 0.73 kJ
Learn more about freezing:brainly.com/question/3121416
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