<h3>
Answer:</h3>
0.00245 moles of HCl
<h3>
Explanation:</h3>
We are given;
Volume of KOH = 9.71 mL
Molarity of KOH = 0.252 M
Volume of HCl = 15.0 mL
We are required to determine the number of moles of HCl
<h3>Step 1: Write the balanced equation for the reaction</h3>
The reaction between HCl and KOH is given by;
KOH(aq) + HCl(aq) → KCl(aq) + H₂O(l)
<h3>Step 2: Calculating the number of moles of KOH</h3>
Molarity = Moles ÷ Volume
Rearranging the formula;
Moles = Molarity × Volume
= 0.252 M × 0.00971 L
= 0.00245 moles
<h3>Step 3: Moles of HCl </h3>
From the equation, 1 mole of KOH reacts with 1 mole of HCl
Therefore, the mole ratio of KOH : HCl is 1 : 1
Thus,
Moles of HCl will be 0.00245 moles
Therefore, there are 0.00245 moles of HCl in the solution.
Half life is determined using the equation expressed as:
A = Ao e^-kt
First, we need to find for the value k.
A = .67Ao = Ao e<span>^-k(33 min)
k = 0.0121
The half-life is then calculated as follows:
</span>A = .5Ao = Ao e<span>^-0.0121(t)
</span><span>t = 57.28 min
</span>
The answer to your question is D. Sound waves travel faster in more dense material, and the more dense the material the louder the sound is.
Answer : Total molecules that will be needed to visualize a single egg will be 78500 molecules of dye.
Explanation : As a single egg cell has an approximately diameter of 100 μm.
We can use this formula to calculate area of the cell membrane;
A = π ;
We can take π as 3.14 and we get;
A = 3.14 X
Soving we get;
A = 7850 μ
Here we have to calculate the amount of dye molecules which will be needed for 10 fluorescent molecules / μ but;
here 1 μ = 7850 μ dye molecules.
Therefore, 10 fluorescent molecules will need;
7850 X 10 = 78500 molecules of dye.
Therefore, the answer is 78500 molecules of dye.