The answer is helium 0.09 kg/m³.
The wave will move faster in the gas that is having lowest density.
As comparison to other gases-hydrogen, oxygen and radon; helium has the lowest density that is 0.09 kg/m³.
So, waves will move fastest in helium gas as it is having lowest density.
So the answer is helium gas that is waves will move fastest in helium gas.
We know,

For given reaction, 

For , 2.41 moles of
:

We know :

Hence, this is the required solution.
Layer 2 and layer 9 are the same relative age.
Explanation:
The statement that best describes the rock layers is that Layer 2 and layer 9 are the same relative age..
The relative age is used in placing sedimentary rocks in order of their occurrence.
To do this, we apply the sedimentary laws.
The ones applicable here are:
- Principle of superposition states that in an undisturbed sequence, the oldest layer is at the base and youngest on top.
- Principle of cross cutting states that a fault and intrusion are younger than the rocks they cut through.
- Principle of fossil and fauna succession states that fossils and fauna succeed on another in a determinable form.
We see that layers 2 and 9 have the same fossil and are the same lithological units.
learn more:
Sedimentary rocks brainly.com/question/2740663
#learnwithBrainly
Water has a molar mass of 18.015 g/mol . This means that one mole of water molecules has a mass of 18.015 g . So, to sum this up, 6.022⋅1023 molecules<span> of water will amount to 1 mole of water, which in turn will have a mass of 18.015 g . 2.7144moles H2O ⋅</span>6.022<span>⋅1023molec.1mole H2O =1.635⋅1024molec.</span>
Answer:
Hence the correct option is an option (b) Sr4, Cl,Br−,Na+.
Explanation:
Bromine and chlorine belong to an equivalent group. As we go down the group the dimensions increases which too there's a charge on the bromine atom. therefore the size of the Br- is going to be larger in comparison to the chlorine atom.
Sr atom is within the second group, and also it's below the above-mentioned atoms.so Sr is going to be the larger one among all the atoms.
Sodium and chlorine belong to an equivalent period .size decrease from left to right. but due to the charge on sodium its size decreases and there's an opportunity that Na+ size could be adequate for Cl.
Here we finally assume that two atoms are of an equivalent size (Na+ and Cl) which are less in size compared to the opposite two(Sr and Br-) during which one is greater (Sr)and the opposite is smaller(Br-).