Answer: Tfinal = 7.1°C
Explanation:
heat released or absorbed = mass × specific heat capacity × change in temperature
q = m × cg × ΔT (eqn 1)
Note: ΔT = (Tfinal - Tinitial)
(q = ? ΔHsoln=25.7kJ/mole = 25700J/mole; mass of solution, m = 100 + 35g = 135g; cg = specific heat capacity of water = 4.18 J°C-1g-1; ΔT = ? masss of solute, NH4NO3 = 35g, molar mass of solute, NH4NO3 = 80g)
molar enthalpy of solution, ΔHsoln
<em> = heat absorbed or released ÷ moles of solute, </em><em>n</em>
ΔHsoln = q ÷ n
q = ΔHsoln × n
<em>moles solute</em>, n = mass solute (g) ÷ molar mass solute (g mol-1)
moles of solute, n = 35g/80g/mol = 0.4375 moles
q = 25700J/mol × 0.4375 mol = 11243.75J
From equation 1 above, ΔT = q / (m × cg) = 11243.75J / (135 × 4.18 J°C-1g-1) = 19.9°C
Since the reaction is endothermic, Tinitial > Tfinal, therefore, Tfinal = Tinitial - ΔT = 27 - 19.9 = 7.1°C
Answer:
0.78 M
Explanation:
First, we need to know which is the value of Kc of this reaction. In order to know this, we should take the innitial values of N2, O2 and NO and write the equilibrium constant expression according to the reaction. Doing this we have the following:
N2(g) + O2(g) <------> 2NO(g) Kc = ?
Writting Kc:
Kc = [NO]² / [N2] * [O2]
Replacing the given values we have then:
Kc = (0.6)² / (0.2)*(0.2)
Kc = 9
Now that we have the Kc, let's see what happens next.
We add more NO, until it's concentration is 0.9 M, this means that we are actually altering the reaction to get more reactants than product, which means that the equilibrium is being affected. If this is true, in the reaction when is re established the equilibrium, we'll see a loss in the concentration of NO and a gaining in concentrations of the reactants. This can be easily watched by doing an ICE chart:
N2(g) + O2(g) <------> 2NO(g)
I: 0.2 0.2 0.9
C: +x +x -2x
E: 0.2+x 0.2+x 0.9-2x
Replacing in the Kc expression we have:
Kc = [NO]² / [N2] * [O2]
9 = (0.9-2x)² / (0.2+x)*(0.2+x) ----> (this can be expressed as 0.2+x)²
Here, we solve for x:
9 = (0.9-2x)² / (0.2+x)²
√9 = (0.9-2x) / (0.2+x)
3(0.2+x) = 0.9-2x
0.6 + 3x = 0.9 - 2x
3x + 2x = 0.9 - 0.6
5x = 0.3
x = 0.06 M
This means that the final concentration of NO will be:
[NO] = 0.9 - (2*0.06)
[NO] = 0.78 M
Neon is an element that has 10 electrons, 10 protons, and most of the time has 10 neutrons in each neon atom. Nitrogen is an element that has 7 electrons, 7 protons, and most often has 7 neutrons in each nitrogen atom. So the Bohr model of a neon atom would be slightly larger than a nitrogen atom.
Question: dot structure for magnesium
Answer: Mg :
The term monomer refers to a unit made up of several atoms.This will make the correct answer B.