Answer:
a. The phenolphthalein acts as a color changing indicator to signal the endpoint of the reaction.
Explanation:
Phenolphthalein is an organic substance with chemical formula
.
It is a substance commonly used in acid-base titrations to indicate the end point in the titration because phenolphthalein is colorless in acidic solutions but turns a purplish-pink color in basic solutions.
In this way it helps visually to notice when the final point of the titration has been reached.
<span>In a mole of anything, there are 6.023 x 10^23 units. So, in 3.9 moles of sulfur, there are 3.9 * 6.023 x 10^23 = 23 x 10^23 = 2.3 x 10^24 atoms (keeping only 2 sig figs). Hope I help!!
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Answer:
v = 23.96 cm³
Explanation:
Given data:
Mass = 15.0 g
Density = 0.626 g/cm³
Volume = ?
Solution:
Formula:
D=m/v
D= density
m=mass
V=volume
Now we will put the values in formula:
d = m/v
v = m/d
v = 15 g / 0.626 g/cm³
v = 23.96 cm³