Answer:
I think is the last one.
Anthracite – Stage Four
Anthracite, the fourth stage in coal formation, is also known as “hard coal” because it is hard and has a high lustre. It appears to have been formed as a result of combined pressure and high temperature. Anthracite burns with a short flame and little smoke.
Calcium Hydroxide (Ca(OH)2) can actually be formed by the
reaction of Calcium Oxide (CaO) with water (H2O). The complete balanced
chemical reaction is:
<span>CaO + H2O
--> Ca(OH)2</span>
<span>The subscript 2 in (OH) means that there are 2 O and 2 H
on the product side. Hence, the equation is balanced already.</span>
The answer is A. For a first-order chemical reaction, the rate constant k has a relationship with concentration C as follow: dC/dT=k*C. So in this reaction, (1-0.5)/30=k*0.5. So k=0.033
Molar mass of O2= 16.0 g/mol
molar mass of H2O= 18.0 g/mol
10.0 g of O2= 5 mol
80.0 g of H20= 5 mol
you need twice as the moles of H2 as O2 so there is insufficient H2 and it is the limiting reactant and all of it will react therefore 5.00 moles of H2 with 2.5 mole of O2 to produce 5.00 moles H2O
5.00 moles of H2O is 5.00x18.00=90.00 g
so the answer is 90.00