I believe that the answers are 3 and 4
I believe the correct answer would be that t<span>he change in enthalpy can be found by adding the enthalpies of the individual thermochemical reactions of a chemical reaction.</span> In Hess' Law, enthalpy is independent of the mechanism of the reaction. The enthalpy should be the sum of all the changes in the reaction.
<h3>
Answer:</h3>
28.96 kJ/°C
<h3>
Explanation:</h3>
We are given;
- Enthalpy change (ΔH) = −3226.7 kJ/mol
- The reaction is exothermic since the heat change is negative;
- Mass of benzoic acid = 3.1007 g
- Temperature change (21.84°C to 24.67°C) = 2.83°C
We are required to find the heat capacity of benzoic acid;
<h3>Step 1: Moles of benzoic acid </h3>
Moles = Mass ÷ molar mass
Molar mass of benzoic = 122.12 g/mol
Therefore;
Moles = 3.1007 g ÷ 122.12 g/mol
= 0.0254 moles
<h3>Step 2: Determine the specific heat capacity </h3>
Heat change for 1 mole = 3226.7 kJ
Moles of Benzoic acid = 0.0254 moles
But;
Specific heat capacity × ΔT = Moles × Heat change
cΔT = nΔH
Therefore;
Specific heat capacity,c = nΔH ÷ ΔT
= (3226.7 kJ × 0.0254 moles) ÷ 2.83°C
= 28.96 kJ/°C
Therefore, the specific heat capacity of benzoic acid is 28.96 kJ/°C
Calcium ions have oxidation state 2+ => Ca (2+).
Bromime ions (bromide) have oxidation state 1- => Br (-).
So, to be neutral the compound has to have two Br (-) ions per each Ca(2+) ion.
That is represented in the chemical formula as Ca Br2, where the number 2 to the right of Br is a subscript meaning that there are two atoms of Br per each atom of Ca (the lack of subscript means 1 atom).
Answer: Ca Br2.
In order to find the number of neutrons in the atom,
you need to calculate the difference between the top and bottom numbers
which means 272 - 111 = 161
Hope this helps
