According to this formula :
㏑[A] /[Ao] = - Kt
when we have Ao = 0.3 m
and K =0.46 s^-1
t = 20min = 0.2 x 60 =12 s
So by substitution :
㏑[A] / 0.3 = - 0.46 * 12
㏑[A] / 0.3 = - 5.52
by taking e^x for both side of the equation we can get [A]
∴[A] = 0.0012 mol dm^-3
A magical or medicinal potion/solution
Leah's experiment:
A. Takes careful and regular measurements (she measures the growth every day)
B. Has a specific hypothesis and a controlled experiment (the music is the only changing variable, the growth conditions are identical, and this is what she wants to test in her hypothesis)
C. Experimental data that can be recorded and analyzed (measuring the growth of plant fits this)
So the answer must be D, since there is no mention of past research that scientists have found on this topic.
The number of atoms of gold in the pure ring are 7.18 × 10²² atoms.
<h3>HOW TO CALCULATE NUMBER OF ATOMS?</h3>
The number of atoms in a substance can be calculated by multiplying the number of moles of the substance by Avogadro's number.
The number of moles in the gold (Au) can be calculated by dividing the mass of gold by its molar mass (196.97g/mol).
no. of moles = 23.5g ÷ 196.97g/mol
no. of moles = 0.119mol
Number of atoms in Au = 0.119 × 6.02 × 10²³
no. of atoms = 7.18 × 10²² atoms.
Therefore, the number of atoms of gold in the pure ring are 7.18 × 10²² atoms.
Learn more about number of atoms at: brainly.com/question/15959704
