Answer:
110 degree
Explanation:
This is because Hybridization of an s orbital with all three p orbitals (px , py, and pz) results in four sp3 hybrid orbitals. sp3 hybrid orbitals are oriented at bond angle of 109.5 degrees from each other. This 109.5 degrees gives an arrangement of tetrahedral geometry
Answer:
ΔH°f(C₈H₁₈(g)) = -210.9 kJ/mol
Explanation:
Let's consider the combustion of C₈H₁₈.
C₈H₁₈(g) + 25/2 O₂(g) ⟶ 8 CO₂(g) + 9 H₂O(g) ΔH°rxn = − 5113.3 kJ
We can calculate the standard enthalpy of formation of C₈H₁₈(g) using the following expression.
ΔH°rxn = 8 mol × ΔH°f(CO₂(g)) + 9 mol × ΔH°f(H₂O(g)) - 1 mol × ΔH°f(C₈H₁₈(g)) - 25/2 mol × ΔH°f(O₂(g))
1 mol × ΔH°f(C₈H₁₈(g)) = 8 mol × ΔH°f(CO₂(g)) + 9 mol × ΔH°f(H₂O(g)) - 25/2 mol × ΔH°f(O₂(g)) - ΔH°rxn
1 mol × ΔH°f(C₈H₁₈(g)) = 8 mol × (-393.5 kJ/mol) + 9 mol × (-241.8 kJ/mol) - 25/2 mol × 0 kJ/mol - (− 5113.3 kJ)
ΔH°f(C₈H₁₈(g)) = -210.9 kJ/mol
The answer is actually C. endorphins. during regular exercise, the pituitary gland and central nervous system produce endorphins
Answer:
619.2 °C
Explanation:
Given data:
Initial volume of gas = 736 mL
Initial temperature = 15°C
Final volume = 2.28 L
Final temperature = ?
Solution:
First of all we will convert the temperature into kelvin and mL into L.
Initial temperature = 15°C (15+273 = 288 k)
Initial volume of gas = 736 mL × 1 L/1000 mL = 0.736 L
The given problem will be solve through the Charles Law.
According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.
Mathematical expression:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
0.736 L / 288 k = 2.28 L / T₂
T₂ = 2.28 L× 288 k/0.736 L
T₂ = 656.64 K /0.736
T₂ = 892.2 K
Kelvin to °C:
892.2 K - 273.15 = 619.2 °C
A substance where almost all have the same atomic number of protons