The mass of watch glass is 24.5 g , the mass of watch glass plus white crystals befor drying is 29.1g , and the mass of watch glass and white crystals after drying 27.9 , thus the mass of the white crystals is !????!
27.9g = mass watch glass + dry xtals
-24.5g = mass MT watch glass
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??? = mass dry xtals.
To find the mass of the white crystals, we need to calculate the difference in mass between the watch glass plus white crystals before drying and the watch glass after drying.
Mass of the watch glass plus white crystals before drying = 29.1 g
Mass of the watch glass after drying = 27.9 g
To find the mass of the white crystals, we subtract the mass of the watch glass after drying from the mass of the watch glass plus white crystals before drying:
Mass of white crystals = Mass of watch glass plus white crystals before drying - Mass of watch glass after drying
= 29.1 g - 27.9 g
= 1.2 g
Therefore, the mass of the white crystals is 1.2 grams.