A hydrate is a substance where in it contains water and other constituent elements. To know whether if that compound was a hydrate,you should record its mass, then put it in a test tube and heat it with a Bunsen burner. If the compound is a hydrate, the water in the compound will discharge in the form of water vapor. At the next 5-10 minutes, remove it in the test tube and weigh it up again. If the mass is now fewer, that means that there was water existing that has now evaporated, and the compound was a hydrate.
I would say the answer is A.
The pressure of the gas : 1.1685 atm
<h3>Further explanation</h3>
In general, the gas equation can be written

where
P = pressure, atm
V = volume, liter
n = number of moles
R = gas constant = 0.08206 L.atm / mol K
T = temperature, Kelvin
n=moles=1.5
V=volumes = 30 L
T=temperature=285 K
The pressure :

The balanced equation for the decomposition of hydrogen peroxide is H₂O₂(aq)→2H₂O(l)+O₂(g).
<h3>What is decomposition reaction?</h3>
Decomposition reactions are those reactions in which a compound will decompose into small molecules.
Hydrogen peroxide will decompose into water molecule and oxygen gas, balanced chemical equation will be represented as:
H₂O₂(aq) → 2H₂O(l) + O₂(g)
Where all atoms are present in equal quantities on both side of the equation.
Hence balanced decomposition reaction of H₂O₂ is H₂O₂(aq)→2H₂O(l)+O₂(g).
To know more about decomposition reaction, visit the below link:
brainly.com/question/27300160
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The average weight of an atom of an element, formerly based on the
weight of one hydrogen atom taken as a unit or on 1/16 (0.0625) the
weight of an oxygen atom, but after 1961 based on 1/12 the weight of the
carbon-12 atom.