Answer:
19.07 g mol^-1
Explanation:
The computation of the molecular mass of the unknown gas is shown below:
As we know that

where,
Diffusion rate of unknown gas = 155 mL/s
CO_2 diffusion rate = 102 mL/s
CO_2 molar mass = 44 g mol^-1
Unknown gas molercualr mass = M_unknown
Now placing these values to the above formula

After solving this, the molecular mass of the unknown gas is
= 19.07 g mol^-1
Answer: The volume of the sample after the reaction takes place is 29.25 L.
Explanation:
The given reaction equation is as follows.

So, moles of product formed are calculated as follows.
Hence, the given data is as follows.
= 0.17 mol,
= 0.255 mol
= 19.5 L, 
As the temperature and pressure are constant. Hence, formula used to calculate the volume of sample after the reaction is as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that the volume of the sample after the reaction takes place is 29.25 L.
Answer:
is the smallest unit of ordinary matter that forms a chemical element.
Explanation:
and were created after the Big Bang 13.7 billion years ago.
Answer:

Explanation:
Hello there!
In this case, according to the given STP (standard pressure and temperature), it is possible for us to realize that the equation to use here is the Avogadro's law as a directly proportional relationship between moles and volume:

In such a way, given the initial volume and both initial and final moles, we can easily compute the final volume as shown below:

Best regards!
I would say A and C. The circulatory system moves blood and nutrients similar to the plant moving water and nutrients. The endocrine system is responsible for hormones, glands and other such functions.