Answer: 1. 
2. 3 moles of 
: 2 moles of 
3. 0.33 moles of : 0.92 moles of
4. is the limiting reagent and is the excess reagent.
5. Theoretical yield of 
is 29.3 g
Explanation:
To calculate the moles :
The balanced chemical equation is:
According to stoichiometry :
3 moles of require = 2 moles of
Thus 0.33 moles of will require=
of
Thus is the limiting reagent as it limits the formation of product and is the excess reagent.
As 3 moles of give = 2 moles of
Thus 0.33 moles of give = of
Theoretical yield of 
Thus 29.3 g of aluminium chloride is formed.
Explanation:
the pH of the solution defined as negatuve logarithm of 
ion concentration.
![pH=-\log[H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D)
1. Hydrogen ion concentration when pH of the solution is 11.
![11=-\log[H^+]](https://tex.z-dn.net/?f=11%3D-%5Clog%5BH%5E%2B%5D)
![[H^+]=1\times 10^{-11} mol/L](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D1%5Ctimes%2010%5E%7B-11%7D%20mol%2FL)
..(1)
At pH = 11, the concentration of ions is 
.
2. Hydrogen ion concentration when the pH of the solution is 6.
![6=-\log[H^+]'](https://tex.z-dn.net/?f=6%3D-%5Clog%5BH%5E%2B%5D%27)
![[H^+]'=1\times 10^{-6} mol/L](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%27%3D1%5Ctimes%2010%5E%7B-6%7D%20mol%2FL)
..(2)
At pH = 6, the concentration of ions is 
.
3. On dividing (1) by (2).
![\frac{[H^+]}{[H^+]'}=\frac{1\times 10^{-11} mol/L}{1\times 10^{-6} mol/L}=1\times 10^{-5}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BH%5E%2B%5D%7D%7B%5BH%5E%2B%5D%27%7D%3D%5Cfrac%7B1%5Ctimes%2010%5E%7B-11%7D%20mol%2FL%7D%7B1%5Ctimes%2010%5E%7B-6%7D%20mol%2FL%7D%3D1%5Ctimes%2010%5E%7B-5%7D%20)
The ratio of hydrogen ions in solution of pH equal to 11 to the solution of pH equal to 6 is 
.
4. Difference between the ions at both pH:
This means that Hydrogen ions in a solution at pH = 7 has 
ions fewer than in a solution at a pH = 6
a) The reaction is exothermic since the overall enthalpy change is negative. this means that the system has lost energy to the environment, namely, the apparatus and due to drought.
b) We first calculate the number of moles in 3.55 grams of magnesium.
number of moles= mass/ atomic mass
=3.55/24
=0.1479 moles(to 4sf)
now, if 2 moles of magnesium give -1204kJ
How much energy is given by 0.1479 moles
= (0.1479×-1204kJ)
=-89.0358kJ (don't forget the negative sign)
c) two molesof MgO produces -1204kJ of energy
then -234kJ will be produced by
=(-234kJ×2moles)/1204kJ
=0.3887moles
one mole of MgO weighs 24+16=40
therefore the mass produced is 0.3887moles×40=15.548grams
(d) we first find the number of moles of MgO in 40.3 grams
number of moles=mass/RFM
=40.3g/40= 1.0075moles
if 2 moles of MgO give 1204 kJ then decomposing 1.0075 moles requires
(1.0075 moles×1204kJ)/2=606.515kJ
Answer:
C. cooler than both the crust and the core
Explanation:
It is observed that at the mantle, temperatures range from estimatedly 200 °C (392 °F) around the upper boundary with the crust to approximately 4,000 °C (7,230 °F) at the core-mantle boundary.
So we can say the mantle is cooler than both the crust and the core.
Answer:
expands
Explanation:
Most substances become increasingly compressed when frozen solid, but water is a famous exception.
