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:
If temperature increases, as it does in most reactions, a chemical change is likely to be occurring. This is different from the physical temperature change. During a physical temperature change, one substance, such as water is being heated.
Explanation:
Answer:
3.74 x 10²² particles
Explanation:
Given parameters:
Mass of compound = 1.43g
Molar mass of compound = 23g
Unknown:
Number of particles of sodium = ?
Solution:
To find the number of particles of Na in the compound, we need to obtain the mass of sodium from the total mass given;
Mass of sodium = 
= 
= 1.43g
Now find the number of moles of this amount of Na in the sample;
Number of moles = 
= 
= 0.062mole
Now;
1 mole of substance = 6.02 x 10²³ particles
0.062 mole of substance = 0.062 x 6.02 x 10²³ particles
= 3.74 x 10²² particles
