Answer:
2. 
3. 
Explanation:
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2. In this case, we can evidence the problem by which volume and temperature are involved, so the Charles' law is applied to:

Thus, considering the temperatures in kelvins and solving for the final volume, V2, we obtain:

Therefore, we plug in the given data to obtain:

3. In this case, it is possible to realize that the 3.7 moles of neon gas are at 273 K and 1 atm according to the STP conditions; in such a way, considering the ideal gas law (PV=nRT), we can solve for the volume as shown below:

Therefore, we plug in the data to obtain:

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Answer:
Pure compounds include elements and compounds where a combination of two or more pure substances is a mixture. Only one type of atom comes in the form of a pure element. Multiple atoms consist of a molecule and different atoms consist of a compound. These are all pure substances and individually.
Answer:
The type of reaction for the following equation is combustion equation.
Explanation:
Combustion reaction is defined as the chemical reaction in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide gas and water molecule.

The reaction given to us:

When 1 mole of ethane reacts with 7/2 moles of oxygen gas it gives 3 moles of water and 2 moles of carbon dioxide gas.
The type of reaction for the following equation is combustion equation.