Answer:
The answer is: D
Explanation:
A. They have the same number of electron energy shells. Is false, all the elements are in different periods so, they have different number of lectron energy shells.
B. They are all Halogens. No, is wrong, halogens are F, Cl ,Br
C. They have the same number of electrons. is wrong, if they had the same number of electrons they must be they same element and they aren't the same.
D. They are all Noble gases. Yes, it's true they are noble gases, they are the first group in the periodic table from the right.
Answer:
0.027 M HCl
Explanation:
The chemical equation of the neutralization is:
1 NaOH + 1 HCl -> 1 H2O + 1 NaCl
Because the ratio of NaOH and HCl is 1:1 you can use the M1V1=M2V2 formula.
(75 mL)(0.5 M NaOH) = (165 mL)(M HCl)
It requires 0.027 M HCl.
C is your answer. Because if you add two of them together you get a compound.
Definition: Cubic centimeter. A cubiccentimetre (cm3) is equal to thevolume of a cube with side length of 1 centimetre. It was the base unit ofvolume of the CGS system of units, and is a legitimate SI unit. It is equal to a millilitre (ml).
Convert ml to cm cubed - Conversion of Measurement Units
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