Answer:
The ΔH of the reaction is + 12.45 KJ/mol
Explanation:
Mass of water= 100ml = 100g. (You should always assume 1cm3 of water as 1g)
heat capacity of water = 4.18 Jk-1 Mol-1
Change in temperature = (19.86 - 25.00) = -5.14 K (This is an endothermic reaction because of the fall in temperature)
Molar mass of NaHCO3 = 84 g/mol
Mole of NaHCO3 = 14.5 / 84 = 0.173 mol
Step 1 : Calculate the heat energy (Q) lost by the water.
Q = M x C x ΔT
Q = -100 x 4.18 x (-5.14)
Q = 2148.5 joules
Q = 2.1485 K J
Step 2: Calculating the ΔH of the reaction?
ΔH = Q / number of moles of NaHCO3
ΔH = 2.1485 / 0.173
ΔH = 12.42 KJ/mol
Answer: Most methods for making new elements involve a cyclotron, which speeds up atoms to high velocities before they smash into other atoms—these atoms are usually of different elements. This causes the nuclei to combine, creating new heavier elements.
Explanation: How are superheavy elements made?
To
determine the percent ionization of the acid given, we make use of the acid
equilibrium constant (Ka) given. It is the ration of the equilibrium
concentrations of the dissociated ions and the acid. The dissociation reaction
of the HF acid would be as follows:<span>
HF = H+ + F-
The acid equilibrum constant would be expressed as follows:
Ka = [H+][F-] / [HF] = 3.5 x 10-4
To determine the equilibrium concentrations we use the ICE table,
HF
H+ F-
I 0.337 0
0
C -x +x
+x
---------------------------------------------
E 0.337-x x
x
3.5 x 10-4 = [H+][F-] / [HF]
3.5 x 10-4 = [x][x] / [0.337-x] </span>
Solving for x,
x = 0.01069 = [H+] = [F-]
percent ionization = 0.01069 / 0.337 x 100 = 3.17%
An oxidation-reduction (redox<span>) </span>reaction<span> is a type of chemical </span>reaction<span> that involves a transfer of electrons between two species. An oxidation-reduction </span>reaction<span> is any chemical </span>reaction<span> in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.</span>
