Answer:
The answer to your question is letter B. 9
Explanation:
Unbalanced reaction
Al₂(SO₄)₃ + Ca(OH)₂ ⇒ Al(OH)₃ + CaSO₄
Reactants Elements Products
2 Al 1
3 S 1
14 O 7
1 Ca 1
2 H 3
Balanced reaction
Al₂(SO₄)₃ + 3Ca(OH)₂ ⇒ 2Al(OH)₃ + 3CaSO₄
Reactants Elements Products
2 Al 2
3 S 3
18 O 18
3 Ca 3
6 H 6
The sum of the coefficients is 1 + 3+ 2+ 3 = 9
Answer:
The correct option is C
Explanation:
From the question we are told that
The reaction is

Generally
Here
is the change in enthalpy
is the change in the internal energy
is the difference between that number of moles of product and the number of moles of reactant
Looking at the reaction we can discover that the elements that was consumed and the element that was formed is
and
and this are both gases so the change would occur in the number of moles
So
The negative sign in the equation tell us that the enthalpy
would be less than the Internal energy 
Bronze alloy and porcelain dentures
the answer is "There is an outside energy source." in voltaic cells, there is not need of an external source of energy because they involve spontaneous reactions.
in both types of cells, the electrons move from anode to cathode, the anode is where oxidation takes place and cathode for reduction (an ox, red cat). also both have two half reactions.
When you see a long dash joining two elements in the structural formula of a chemical molecule you can assume that the chemical bonds in the compound are simple bonds.
In the representation of chemical molecules long dashes are used to represent simple bonds since these bonds are longer than double and triple bonds, which are represented by = and ≡ respectively.