The question is incomplete, here is the complete question:
At elevated temperature, nitrogen dioxide decomposes to nitrogen oxide and oxygen gas

The reaction is second order for
with a rate constant of
at 300°C. If the initial [NO₂] is 0.260 M, it will take ________ s for the concentration to drop to 0.150 M
a) 1.01 b) 5.19 c) 0.299 d) 0.0880 e) 3.34
<u>Answer:</u> The time taken is 5.19 seconds
<u>Explanation:</u>
The integrated rate law equation for second order reaction follows:
![k=\frac{1}{t}\left (\frac{1}{[A]}-\frac{1}{[A]_o}\right)](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B1%7D%7Bt%7D%5Cleft%20%28%5Cfrac%7B1%7D%7B%5BA%5D%7D-%5Cfrac%7B1%7D%7B%5BA%5D_o%7D%5Cright%29)
where,
k = rate constant = 
t = time taken = ?
[A] = concentration of substance after time 't' = 0.150 M
= Initial concentration = 0.260 M
Putting values in above equation, we get:

Hence, the time taken is 5.19 seconds
Answer:
Alpha particle
Explanation:
The helium symbol is also used to represent he alpha particles.
For example:
The americium with atomic wight 224 undergo alpha decay and produce
₉₃Np²³⁷ . The alpha particle emitted is also called helium nuclei. During this decay some gamma radiations also produce as a byproduct.
₉₅Am²²⁴ → ₉₃Np²³⁷ + ₂He⁴
Properties of alpha radiation:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
Answer:
Explanation:
Mechanical digestion involves physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion. The role of chemical digestion is to further degrade the molecular structure of the ingested compounds by digestive enzymes into a form that is absorbable into the bloodstream.
M1 = 17.45 M
M2 = 0.83 M
V2 = 250 ml
M1. V1= M2. V2
V1 = (M2. V2)/M1 = (0.83× 250)/ 17.45= 11.89 ml
<u>Answer:</u> The correct IUPAC name of the alkane is 4-ethyl-3-methylheptane
<u>Explanation:</u>
The IUPAC nomenclature of alkanes are given as follows:
- Select the longest possible carbon chain.
- For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.
- A suffix '-ane' is added at the end of the name.
- If two of more similar alkyl groups are present, then the words 'di', 'tri' 'tetra' and so on are used to specify the number of times these alkyl groups appear in the chain.
We are given:
An alkane having chemical name as 3-methyl-4-n-propylhexane. This will not be the correct name of the alkane because the longest possible carbon chain has 7 Carbon atoms, not 6 carbon atoms
The image of the given alkane is shown in the image below.
Hence, the correct IUPAC name of the alkane is 4-ethyl-3-methylheptane