Answer:
The correct answer is skeleton equation.
Explanation:
In chemistry, the skeletal formula of a compound is an abbreviated representation of its molecular structure. Skeleton formulas are used because they clearly show complicated structures, they are fast and simple to draw.
All atoms that are not carbon or hydrogen are represented by their chemical symbol. The relative amounts of reagents and products are not indicated.
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<u>Answer:</u> The time taken by the reaction is 84.5 seconds
<u>Explanation:</u>
The equation used to calculate half life for first order kinetics:
where,
= half-life of the reaction = 9.0 s
k = rate constant = ?
Putting values in above equation, we get:
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)
......(1)
where,
k = rate constant = 
t = time taken for decay process = 50.7 sec
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the reactant = ?
[A] = amount left after decay process = 0.0741 M
Putting values in equation 1, we get:
![0.077=\frac{2.303}{50.7}\log\frac{[A_o]}{0.0741}](https://tex.z-dn.net/?f=0.077%3D%5Cfrac%7B2.303%7D%7B50.7%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B0.0741%7D)
![[A_o]=3.67M](https://tex.z-dn.net/?f=%5BA_o%5D%3D3.67M)
Now, calculating the time taken by using equation 1:
![[A]=0.0055M](https://tex.z-dn.net/?f=%5BA%5D%3D0.0055M)
Putting values in equation 1, we get:
Hence, the time taken by the reaction is 84.5 seconds
<u>Answer:</u>
Pyrite leaves behind a green-black streak when it is rubbed against an unglazed porcelain plate as a part of the streak test process.
<u>Explanation:</u>
Different minerals produce different coloured streaks when rubbed against a white ceramic or porcelain streak plate. This streak test is done to identify the mineral and distinguish the same from other minerals that look similar in colour and texture.
It must be ensured that the test is done on clean and fresh specimens of the mineral and that there must be no contaminants. Pyrite specimens are usually brass-yellow colour but it leaves a green-black streak when the streak test is done.
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Project: Modeling potential and kinetic energy
Assignment Summary
For this assignment, you will develop a model that shows a roller coaster cart in four different positions on a track. You will then use this model to discuss the changes in potential and kinetic energy of the cart as it moves along the track.
Background Information
The two most common forms of energy are potential energy and kinetic energy. Potential energy is the stored energy an object has due to its position. Kinetic energy is the energy an object has due to its motion. An object’s kinetic energy changes with its motion, while its potential energy changes with its position, but the total energy stays the same. If potential energy increases, then kinetic energy decreases. If potential energy decreases, then kinetic energy increases.
Potential energy related to the height of an object is called gravitational potential energy. Gravitational potential energy is directly related to an object’s mass, the acceleration due to gravity, and an object’s height.
Materials
One poster board per student Drawing utensils
Assignment Instructions
Step 1: Prepare for the project.
a) Read the entire Student Guide before you begin this project.
b) If anything is unclear, be sure to ask your teacher for assistance before you begin.
c) Gather the materials you will need to complete this project.
Step 2: Create your poster.
a) On the poster board, draw a roller coaster track that starts with one large hill, then is followed by a valley and another, smaller hill.
b) Draw a cart in four positions on the track as outlined below.
i. Draw the first cart at the top of the first hill. Label it A.
ii. Draw the second cart going down the first hill into the valley. Label it B.
iii. Draw the third cart at the bottom of the valley. Assume that the height of the cart in this position is zero. Label it C.
iv. Draw the last cart at the top of the second, smaller hill. Label it D.
c) Make sure that your name is on the poster. Step 3: Type one to two paragraphs that describe the energy of the cart.
a) Type one to two paragraphs describing the changes in potential and kinetic energy of the cart. Be sure to discuss how the potential and kinetic energy of the cart changes at each of the four positions along the track, and explain why these changes occur.
b) Make sure your name is on the document.
c) Later, you will submit this document through the virtual classroom.
Step 4: Evaluate your project using this checklist.
If you can check each criterion below, you are ready to submit your project.
Did you draw a model of a roller coaster track with one large hill, a valley, and a smaller hill?
Did you draw a cart on the track in the four required positions A–D? Did you label the cart at each of the four positions?
Did you type a paragraph describing the changes in potential and kinetic energy of the cart at each of the four positions on the roller coaster track? Did you explain why the changes in potential and kinetic energy occur?
Step 5: Revise and submit your project.
a) If you were unable to check off all of the requirements on the checklist, go back and make sure that your project is complete.
b) When you have completed your project, submit your poster to your teacher for grading. Be sure that your name is on it.
c) Submit the typewritten document through the virtual classroom. Be sure that your name is on it.
Step 6: Clean up your work space.
a) Clean up your work space. Return any reusable materials to your teacher and throw away any trash.
b) Congratulations! You have completed your project.
Electric energy and sink
Amphiprotic compounds are able to both donate and accept a proton.
Amphiprotic compounds contain a hydrogen atom and lone pair of valence electron.
For example, HSO₃⁻ (hydrogen sulfate ion) is an amphiprotic compound.
Balanced chemical equation for reaction when HSO₃⁻ donate protons to water:
HSO₃⁻(aq) + H₂O(l) ⇄ SO₄²⁻(aq) + H₃O⁺(aq).
Ka = [SO₄²⁻] · [H₃O⁺] / [HSO₃⁻]
Balanced chemical equation for reaction when HSO₃⁻ accepts protons from water:
HSO₃⁻(aq) + H₂O(l) ⇄ H₂SO₄(aq) + OH⁻(aq).
Kb = [H₂SO₄] · [OH⁻] / [HSO₃⁻]
Water (H₂O), amino acids, hydrogen carbonate ions (HCO₃⁻) are examples of amphiprotic species.
Another example, water is an amphiprotic substance:
H₂O + HCl → H₃O⁺ + Cl⁻
H₂O + NH₃ → NH₄⁺ + OH⁻
More about amphiprotic compounds: brainly.com/question/3421406
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