Mixture would be the piece of pure gold. I don't know the explanation but the answer is mixture, I'm sure about that it is mixture, I read it somewhere.
<span>An explosion that releases great amounts of heat is an example of an exothermic process. Any reaction that gives off or releases energy as light, electricity, heat, or sound is considered to be exothermic, with "exo" meaning "outside". An explosion is one of the most extreme cases of exothermic reactions.</span>
Answer:
4.43L is final volume of the ballon
Explanation:
Avogadro's law of ideal gases states that <em>equal volumes of gases, at the same temperature and pressure, have the same number of molecules</em>.
The formula is:

Where V and n are volume and moles of the gas in initial and final conditions.
If the initial conditions are 0.0145 moles and 2.54L and final amount of moles is 0.0253moles, final volume is:

V₂ = <em>4.43L is final volume of the ballon</em>