Chelp meeee this is science btw but eahhhh
2 answers:
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Answer:
Explanation:
We are given a number of particles and asked to convert to moles.
<h3>1. Convert Particles to Moles </h3>1 mole of any substance contains the same number of particles (atoms, molecules, formula units) : 6.022 *10²³ or Avogadro's Number. For this question, the particles are not specified.
So, we know that 1 mole of this substance contains 6.022 *10²³ particles. Let's set up a ratio.
We are converting 2.98*10²³ particles to moles, so we multiply the ratio by that value.
The units of particles cancel.
The original measurement of particles (2.98*10²³) has 3 significant figures, so our answer must have the same.
For the number we found, 3 sig figs is the thousandth place.
The 8 in the ten-thousandth place (0.4948522086) tells us to round the 4 up to a 5 in the thousandth place.
2.98*10²³ particles are equal to approximately <u>0.495 moles.</u>
Answer:
the value of molar absorptivity is 229000
Explanation:
given data
phenol phthalein solution = 0.050 g
total volume = 100.0 ml
dilute = 100.0 ml
diluted sample = 0.18
solution
we get here concentration that is express as
concentration = ( mass of solute × 1000 ) ÷ ( molar mass of solute × volume of solution ) .............1
put here value
concentration =
concentration = 0.00157 M
and here dillution equation is express as
c1 × v1 = c2 × v2 .................2
here c1 and c2 is initial and final concentration
and v1 and v2 is initial and final volume
put here value
0.001571 × 0.050 = c2 × 100
c2 = 7.855 × M
and
now we get molar by absorbance equation that is
A = E × C × l ................3
here A is absorbance and E is molar and c is absorptivity and l is path length
put here value
0.18 = E × 7.855 × × 1
E = 229000