The piece of evidence would suggest an unknown substance is an ionic compound is that it conducts electricity when dissolved in water.
An exothermic reaction is a chemical reaction that releases energy by light or heat.
<u>Answer:</u> The number of moles of gas in bicycle tire is 0.210 moles
<u>Explanation:</u>
To calculate the moles of gas, we use the equation given by ideal gas which follows:

where,
P = pressure of the gas = 737 torr
V = Volume of the gas = 5.30 L
T = Temperature of the gas = ![25^oC=[25+273]K=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B25%2B273%5DK%3D298K)
R = Gas constant = 
n = number of moles of gas = ?
Putting values in above equation, we get:

Hence, the number of moles of gas in bicycle tire is 0.210 moles
The solution would be like
this for this specific problem:
<span>(78.6 kJ) / (92.0 g /
(46.0684 g C2H5OH/mol)) = 39.4 kJ/mol </span>
<span>39.3 </span>
So the approximate molar
heat of vaporization of ethanol in kJ/mol is 39.3.
I hope this answers your question.