Ca(OH)2(aq) + 2HCl(aq)------> CaCl2(aq) + 2H2O(l) ΔH-?
CaO(s) + 2HCl(aq)-----> CaCl2(aq) + H2O(l), Δ<span>H = -186 kJ
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CaO(s) + H2O(l) -----> Ca(OH)2(s), Δ<span>H = -65.1 kJ
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1) Ca(OH)2 should be reactant, so
CaO(s) + H2O(l) -----> Ca(OH)2(s)
we are going to take as
Ca(OH)2(s)---->CaO(s) + H2O(l), and ΔH = 65.1 kJ
2) Add 2 following equations
Ca(OH)2(s)---->CaO(s) + H2O(l), and ΔH = 65.1 kJ
<span><u>CaO(s) + 2HCl(aq)-----> CaCl2(aq) + H2O(l), and ΔH = -186 kJ</u>
</span>Ca(OH)2(s)+CaO(s) + 2HCl(aq)--->CaO(s) + H2O(l)+CaCl2(aq) + H2O(l)
Ca(OH)2(s)+ 2HCl(aq)---> H2O(l)+CaCl2(aq) + H2O(l)
By addig these 2 equation, we got the equation that we are needed,
so to find enthalpy of the reaction, we need to add enthalpies of reactions we added.
ΔH=65.1 - 186 ≈ -121 kJ
Answer:
a) 
is the mass of 1 mole of bricks.
b) 
moles of bricks have a mass equal to the mass of the Earth.
Explanation:
a) Mass of brick = 4.0 kg
1 mole = 
particles/ atoms/molecules
Mass of 
bricks :
is the mass of 1 mole of bricks.
b)
Mass of the Earth = M = 
Mass of 1 mole of brick = m=
Let the moles of brick with equal mass of the Earth be x.
moles of bricks have a mass equal to the mass of the Earth.
Answer:
its d, forming a hypothesis is always one of the first things you do, and d is the best answer from these 4
