If the sun was not there the earth would travel in a straight line
Answer:Answer: The step that is NOT necessary to complete before a cuvette is placed into the spectrophotometer is option B (Write, in ink, either sample or blank on the side of the cuvette to keep track of them)
Explanation: spectrophotometer is an instrument used to measure the light intensity absorbed after being passed through a solution. Before the absorbance of the sample solution, a solvent solution called blank is used for the calibration of the machine and this blank solvent is placed in a cuvette. The procedure usually comes first before the main sample is processed. Therefore there is no need to
Write, in ink, either sample or blank on the side of the cuvette to keep track of them. This is so since sample and blank is not absorbed at the same time by the machine.
Answer:
2Na + Br2 = 2NaBr
Explanation:
In order to balance a chemical equation you make the make sure both sides have the same number of atoms on each side, you do this by multiplying on both sides as if it was a algebraic equation.
Na+ Br2 = NaBr
Na × 2 = Na2
Na × 2 = Na2
Br × 2 = Br2
2Na + Br2 = 2NaBr
Hope this helps.
The two things are hypothesis and empirical evidence
The mass of sulfur in the sample is 0.31g
To calculate mass of sulfur in sample: given that amount galena is 2.34g and mass of lead is 2.03 g as galena contain both lead and sulfur the mass of sulfur = mass of galena- mass of lead , that is, 2.34- 2.03=0.31g.The molecular mass is a algebraic sum of atomic mass of each element in the compound thus the mass of the compound can be obtained by adding atomic of each element. Lead(II) sulphide occurs naturally as the mineral galena, often known as lead glance (PbS). It is a significant source of silver and the most significant lead ore.
To learn more about mass:
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