Answer:
-21 kJ·mol⁻¹
Explanation:
Data:
H₃O⁺ + OH⁻ ⟶ 2H₂O
V/mL: 50 50
c/mol·dm⁻³: 1.0 1.0
ΔT = 4.5 °C
C = 4.184 J·°C⁻¹g⁻¹
C_cal = 50 J·°C⁻¹
Calculations:
(a) Moles of acid
So, we have 0.050 mol of reaction
(b) Volume of solution
V = 50 dm³ + 50 dm³ = 100 dm³
(c) Mass of solution
(d) Calorimetry
There are three energy flows in this reaction.
q₁ = heat from reaction
q₂ = heat to warm the water
q₃ = heat to warm the calorimeter
q₁ + q₂ + q₃ = 0
nΔH + mCΔT + C_calΔT = 0
0.050ΔH + 100×4.184×4.5 + 50×4.5 = 0
0.050ΔH + 1883 + 225 = 0
0.050ΔH + 2108 = 0
0.050ΔH = -2108
ΔH = -2108/0.0500
= -42 000 J/mol
= -42 kJ/mol
This is the heat of reaction for the formation of 2 mol of water
The heat of reaction for the formation of mol of water is -21 kJ·mol⁻¹.
Answer:
NaCl + Fe2+ ---> FeCl2 + Na+
Single replacement
Explanation:
Na is replaced by Fe2+ to form FeCl2, and that is the only replacement. Thus, it is single replacement.
The nitrogen atom in NH3 is sp3 hybridized. ... In NH3 molecule, three of the sp3 orbitals are used to formbonds to the three hydrogen atoms and the fourth sp3 orbital is used to hold the lone pair. and is sometimes called a non-bonding pair.
Blank 1: polar
The difference in electronegativity between N and H causes electrons to preferentially orbit N, making the bond polar.
Blank 2: trigonal pyramidal
There are four “things” attached to N - 3 H’s and 1 lone pair of electrons. The four things together are arranged into a tetrahedral formation. However, the lone pairs don’t actually contribute to the shape of the molecule per se; it’s only the actual atoms that do. The lone pair creates a bit of repulsion that pushes the 3 H’s down, creating a trigonal pyramidal shape (as opposed to a trigonal planar one).
Blank 3: polar
The molecule as a whole is also polar because the “things” around it, though arranged in a tetrahedral pattern, are not all the same. The side of the molecule with the lone pair is slightly negative, while the side with the 3 H’s is slightly positive due to the differences in electronegativity described above.
Answer:
Molarity = 0.4M
Explanation:
Molar mass of NaOH (M)= 40
m= 8g, V= 500ml=0.5L
n= m/M=[8/40]= 0.2mol
Applying
n= CV
0.2= C×0.5
C= 0.4M
