We can find the principal level or lower level
using Rydberg's formula:
1/w = R(1/L² - 1/U²)
<span>where:</span>
<span>w is the
wavelength (93.8 nm),</span>
L is the lower energy level (unknown)
U the upper energy level (n= 6)
R is Rydberg's constant (10,967,758
waves per meter)
Substituing known values into the equation:<span>
1/(9.38 * 10^-8 m.) = 10,967,758(1/L² - 1-36) </span>
Using the solver function of the calculator to
get for L:
L = 0.999 <span>
so L = 1.
<span>The lower level is 1 (the ground state).</span></span>
The number of hours required : 37.2 hours
<h3>Further explanation</h3>
Given
⁴²K (potassium -42)
Required
The number of hours
Solution
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
Based on Table N(attached), the half-life for ⁴²K is 12.4 hours, which means half of a sample of ⁴²K will decay in 12.4 hours
For three half-life periods :
<u>Answer:</u> The percent yield of the compound is 30.86 %.
<u>Explanation:</u>
To calculate the percentage yield of a compound, we use the equation:
Experimental yield of compound = 25 g
Theoretical yield of compound = 81 g
Putting values in above equation, we get:
Hence, the percent yield of the compound is 30.86 %.
Answer:
Your question is not complete, but use this answer as a guide for your solution.
Question: A chemistry student weighs out 0.112g of acetic acid (HCH₃CO₂) into a 250. mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1600 <em>M</em> NaOH solution. Calculate the volume of solution the student will need to add to reach the equivalence point. Be sure your answer has the correct number of significant digits.
Answer: Volume of NaOH is 11.6 mL
Explanation:
The reaction of acetic acid with NaOH is as follows:
CH3COOH + NaOH -----> CH3COONa + H2O
M1V1 = M2V2
Here M1 V1 are molarity and volume of acetic acid.
M2, V2 are molarity and volume of NaOH.
Number of moles of acetic acid:
0.112 g CH3COOH × (1 mol / 60.05 g) = 0.001865 mol
Molarity = moles of solute / Liters of solution
Molarity = 0.001865 mol / 0.250 L = 0.00746 M
Hence,
M1 = 0.00746 M
V1 = 250 mL
M2 = 0.160 M
V2 = ?
V2 = M1V1 / M2
V2 = 0.00746 M × 250 mL / 0.160 M
V2 = 11.6 mL
Hence the volume of NaOH is 11.6 mL
