In the periodic table, there are seven horizontal rows of elements called periods.
Answer:
b) warming up a) wavelength a) blank c) sample
Explanation:
<em>To run a spectrophotometry experiment, begin by </em><em>warming up</em><em> the spectrophotometer and preparing the samples.</em> It is important that the equipment is warmed up for at least 30 minutes before starting the measurements.
<em>Be sure to select the correct </em><em>wavelength</em><em>, then run a measurement on the </em><em>blank</em><em> solution.</em> The selected wavelength depends on the analyte of interest. The black solution contains the same matrix but it doesn´t contain the analyte.
<em>Follow up by running measurements on </em><em>sample</em><em> solutions. Once data is collected, turn off the instrument, clean the area, and discard the samples. </em>The samples are those of unknown concentration that we want to determine.
When water vapor in the atmosphere loses heat and cools down, condensation happens. As the water vapor cools down and condenses, it attaches to small particles of dust floating in the atmosphere, forming tiny liquid water droplets.
Answer : 6.41 moles of silicon are in the sample.
Solution : Given,
Moles of magnesium = 9.62 moles
The given chemical formula for talc is, 
From the given chemical formula we conclude that
The stoichiometry of magnesium and silicon is 3 : 2
3 moles of magnesium is equivalent to 2 moles of silicon
9.62 moles of magnesium will be equivalent to 
moles of silicon
Therefore, the number of silicon present in sample are 6.41 moles.
