Explanation:
When Henri Becquerel investigated the newly discovered X-rays in 1896, it led to studies of how uranium salts are affected by light. By accident, he discovered that uranium salts spontaneously emit a penetrating radiation that can be registered on a photographic plate.
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 :

The correct answer for the question that is being presented above is this one: "<span>16.728 g."</span>
Given that
ΔHsolid = -5.66 kJ/mol.
This means that 5.66 kJ of heat is released when 1 mole of NH3 solidifies
When 5.57 kJ of heat is released
amount of NH3 solidifies = 5.57/5.66 = 0.984 moles
<span>molar mass of NH3 = 17 g/mole </span>
<span>1 mole of NH3 = 17 g </span>
So, 0.984 moles of NH3 = 17 X 0.984 = 16.728 g
Subtract the mass of the solute from the whole solution volume.
Molarity, percent by mass, and percent by volume are all ways to represent concentration.
By dividing the number of moles by the number of liters of water utilized in the solution, we can compute the molar concentration. Here, for instance, 1.25 L of water has entirely dissolved the acetic acid. In order to determine the molar concentration, which is 0.1332 M, divide 0.1665 moles by 1.25 L. A titration is a method for figuring out the concentration of an unknown solution by using a solution with known concentration.
Finding the concentration for each sample's absorbance on the standard curve is the first step in calculating the sample concentration based on the standard curve. The next step is to multiply the concentration by the dilution factor for each sample.
Learn more about concentration here brainly.com/question/10703427
#SPJ4.
Answer:
Average velocity can be calculated by determining the total displacement divided by the total time of travel.
Explanation: