The answer to the question is the first opti.on.A
Density describes how compact or concentrated something is. For example, suppose you have two boxes, one large and one small. ... That means the small box has a higher density than the large box. Density also tells how concentrated or crowded something is.
Answer:
0.049 mol/L.s
Explanation:
The decomposition of hydrogen peroxide is:
![Rate = -\dfrac{\Delta [H_2O_2]}{\Delta t}= \dfrac{\Delta [H_2O_2]}{\Delta t}= \dfrac{ 2 \Delta [H_2O_2]}{\Delta t}](https://tex.z-dn.net/?f=Rate%20%3D%20-%5Cdfrac%7B%5CDelta%20%5BH_2O_2%5D%7D%7B%5CDelta%20t%7D%3D%20%5Cdfrac%7B%5CDelta%20%5BH_2O_2%5D%7D%7B%5CDelta%20t%7D%3D%20%5Cdfrac%7B%202%20%20%5CDelta%20%5BH_2O_2%5D%7D%7B%5CDelta%20t%7D)
The rate of decomposition reaction = the rate of formation of 
= 0.098 mol/L.s
∴
Rate of formation of 
= 0.049 mol/L.s
It is highly reactive and when it is kept in open it does react with the oxygen present in the surroundings and burns therefore it is kept immersed in kerosene and please thank me and if you need more comment
Firstly, the density of any substance is represented by the mass (amount of matter) as divided by the volume(amount of space). According to external websites, the mass of a penny is 2.5 grams.However, the volume of a penny is .35cm to the power of 3 (due to the thickness of the penny being extremely minimal.Thus the amount of density is extremely little). Therefore, the density of a penny is 0.875 g/cm cubed (dimensional analysis).As for an invention that could be used, that is possible with the usage of a series of measurements that can both calculate mass and volume and directly allocate that to attain density
