Answer:
A.Carbon reacting with oxygen to form co2 is not a physical change it's a chemical change :)
A and 3
B and 6
C and 5
D and 1
E and 2
F and 4
This is an incomplete question, here is a complete question.
Consider the second-order decomposition of nitroysl chloride:
At 450 K the rate constant is 15.4 atm⁻¹s⁻¹. How much time (in s) is needed for NOCl originally at a partial pressure of 53 torr to decay to 10.6 torr?
Answer : The time needed for NOCl is, 2.52 seconds.
Explanation : Given,
Rate constant =
Initial partial pressure of NOCl = 56 torr = 0.0737 atm
final partial pressure of NOCl = 14.5 torr = 0.0191 atm
The expression used for second order kinetics is:
where,
k = rate constant
t = time
= concentration at time 't'
= initial concentration
As we know that,
Thus, the expression of second order kinetics will be:
As,
So, ............(1)
Now put all the given values in the above expression 1, we get:
Therefore, the time needed for NOCl is, 2.52 seconds.
Based on atomic mass
Explanation:
Elements were arranged on the first periodic table based on their atomic masses.
The mass of an atom is made up of the mass of the nucleus which contains the protons and neutrons.
- Dimitri Mendeleev was the first person credited for arranging elements periodically.
- He was said to have been inspired while playing his game of solitaire on a train.
- On his table, he left spaces for the atomic masses of elements not yet discovered.
- Today, the periodic table is based on the atomic numbers of elements. This is the number of protons in an atom.
Learn more:
Periodic table brainly.com/question/2690837
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People firstly believe that the planets move in a circular orbit until Newton came up with his hypothesis by inventing calculus so that we could understood and calculated planetary orbits and their accuracy.
<u>Explanation:</u>
- Everyone assumed the planets were perfect circles until Newton came up with an idea. Slowly people would make maps of the orbits that added circles on circles, and they could never really explain about the movement of the planet. They simply say that planets move on circles but they lacked the math to explain or prove it. Then Newton came up with an idea of inventing calculus so that we could understood and calculated planetary orbits and their accuracy.
- Firstly people used their observations and say that the orbits looked like circles, then they developed their models and did the math, and proposed their hypothesizes which were wrong, until Newton came along and tried to match a model that used elliptical orbits and invented the math that allowed him to make predictions with it. His model worked for most planets.
- However he could not explain about the planet Mercury for instance since it was a very strange orbit. Then after the Einstein's theory of General Relativity he could also explain very deeply about it.
- Scientists and Astronomers made hypothesizes that there was another planet orbiting too close to the sun to see with telescopes, called Vulcan, that explained mercury's orbit before Einstein's theory. Then long after we had telescopes which was good enough to see if there was a planet orbiting closer to the sun than mercury.