<u>Answer:</u> The age of the mineral sample is ![1.09\times 10^9yrs](https://tex.z-dn.net/?f=1.09%5Ctimes%2010%5E9yrs)
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:
![t_{1/2}=\frac{0.693}{k}](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D%5Cfrac%7B0.693%7D%7Bk%7D)
where,
= half life of the reaction = ![1.27\times 10^9yrs](https://tex.z-dn.net/?f=1.27%5Ctimes%2010%5E9yrs)
Putting values in above equation, we get:
![k=\frac{0.693}{1.27\times 10^9yrs}=5.46\times 10^{-10}yrs^{-1}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B0.693%7D%7B1.27%5Ctimes%2010%5E9yrs%7D%3D5.46%5Ctimes%2010%5E%7B-10%7Dyrs%5E%7B-1%7D)
We are given:
Mass ratio of K-40 to Ar-40 = 0.812 : 1.00
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = ![5.46\times 10^{-10}yr^{-1}](https://tex.z-dn.net/?f=5.46%5Ctimes%2010%5E%7B-10%7Dyr%5E%7B-1%7D)
t = time taken for decay process = ? yr
= initial amount of the sample = [1.00 + 0.812] = 1.812 grams
[A] = amount left after decay process = 1.00 grams
Putting values in above equation, we get:
![5.46\times 10^{-10}=\frac{2.303}{t}\log\frac{1.812}{1}\\\\t=1.09\times 10^9yrs](https://tex.z-dn.net/?f=5.46%5Ctimes%2010%5E%7B-10%7D%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B1.812%7D%7B1%7D%5C%5C%5C%5Ct%3D1.09%5Ctimes%2010%5E9yrs)
Hence, the age of the mineral sample is ![1.09\times 10^9yrs](https://tex.z-dn.net/?f=1.09%5Ctimes%2010%5E9yrs)
Answer:
The correct answer is True.
Explanation:
In the kidney, the handle of Henle is a fork-like tube located in the nephrons. It is the portion of the nephron that leads from the proximal contoured tubule to the distal contoured tubule. The primary filtrate from the glomerulus passes into the proximal contoured tubule, which connects to the descending branch of the loop of Henle, which has low permeability to ions and urea (solutes) but is very permeable to water.
Have a nice day!
15 protons (atomic number is always the number of protons) 15 electrons because no charge was mentioned so it must be the same as protons 16 neutrons because mass number is the combined number of protons and neutrons
Molar mass of water 18g/mol
Number of mols = 50.0g/18g/mol =2.78 mol
Heat absorbed = 40.7 kj/mol * 2.78 mol = 113.1 kj.
ANSWER
EXPLANATION
Given that
The energy released by the system is 12.4J
Work done on the surrounding is 4.2J
Follow the steps below to find the change in energy
In the given data, energy is said to be released to the surroundings
Recall, that exothermic reaction is a type of reaction in which heat is released to the surroundings. Hence, change in enthalpy is negative
Step 1; Write the formula for calculating change in energy
![\Delta E\text{ }=\text{ q }+\text{ w}](https://tex.z-dn.net/?f=%5CDelta%20E%5Ctext%7B%20%7D%3D%5Ctext%7B%20q%20%7D%2B%5Ctext%7B%20w%7D)
Since heat is released to the surrounding, then q = -12J
Recall, that work done by the system on the surroundings is always negative
Hence, w = -4.2J
Step 2; Substitute the given data into the formula in step 1
![\begin{gathered} \text{ }\Delta E\text{ = q + w} \\ \text{ }\Delta E\text{ }=\text{ -12.4 }+\text{ \lparen-4.2\rparen} \\ \text{ }\Delta E\text{ = -12.4 - 4.2} \\ \text{ }\Delta E\text{ }=\text{ -16.6J} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20%5Ctext%7B%20%20%7D%5CDelta%20E%5Ctext%7B%20%3D%20q%20%2B%20w%7D%20%5C%5C%20%5Ctext%7B%20%20%7D%5CDelta%20E%5Ctext%7B%20%7D%3D%5Ctext%7B%20-12.4%20%7D%2B%5Ctext%7B%20%5Clparen-4.2%5Crparen%7D%20%5C%5C%20%5Ctext%7B%20%20%7D%5CDelta%20E%5Ctext%7B%20%3D%20-12.4%20-%204.2%7D%20%5C%5C%20%5Ctext%7B%20%20%7D%5CDelta%20E%5Ctext%7B%20%7D%3D%5Ctext%7B%20-16.6J%7D%20%5Cend%7Bgathered%7D)
Therefore, the change i