Physical property of gas:
There are a lot, here are some examples:
=> Air
=> Oxygen
=> Carbon dioxide
=> Flourine
=> Phosphine
=> Argon
=> Carbon monoxide
This examples are all gases and each of these gases has its own physical property. The only thing that they makes them the same are that, they are gas with lesser molecules. Usually gas density is lesser compare to the solid or liquid and most gases has undefined melting point.
It actually depends on the percentage of the concentration give. Percentages can be expressed as %mass/mass, %volume/volume or %mass/volume. To keep things simple, let's just assume that it is in %volume/volume. Thus, 13% of 520 mL is pure acid.
Volume of pure acid = 520*0.13 = 67.6 mL
The correct answer is: [B]:
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" N₂ (g) + 3 H₂ (g) → 2 NH₃ <span>(g) " .
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Note of interest:
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This particular reaction is known as the "</span>Haber process" .
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The answer is B because isotopes have the same number of protons and neutrons.