There are several differences between<span> a </span>physical and chemical change<span> in matter or substances. A </span>physical change<span> in a substance doesn't </span>change<span> what the substance is. In a </span>chemical change<span> where there is a </span>chemical<span> reaction, a new substance is formed and energy is either given off or absorbed.</span>
Answer:
-255.4 kJ
Explanation:
The free energy of a reversible reaction can be calculated by:
ΔG = (ΔG° + RTlnQ)*n
Where R is the gas constant (8.314x10⁻³ kJ/mol.K), T is the temperature in K, n is the number of moles of the products (n =1), and Q is the reaction quotient, which is calculated based on the multiplication of partial pressures by the partial pressure of the products elevated by their coefficient divide by the multiplication of the partial pressure of the reactants elevated by their coefficients.
C₂H₂(g) + 2H₂(g) ⇄ C₂H₆(g)
Q = pC₂H₆/[pC₂H₂ * (pH₂)²]
Q = 0.261/[8.58*(3.06)²]
Q = 3.2487x10⁻³
ΔG = -241.2 + 8.314x10⁻³x298*ln(3.2487x10⁻³)
ΔG = -255.4 kJ
The additional information required to calculate the cost of the drive has been distance between the two cities. Thus, option B is correct.
The distance traveled by the object set the cost per unit has been given by the product of the distance and the cost.
<h3>Detail required for calculation cost</h3>
The given question has known cost of the fuel per gallon.
The mileage of the car has been known.
The distance traveled by the car has not been known. Thus, to calculate the cost of the drive, the distance between the two points has to be known. Thus, option B is correct.
Learn more about distance traveled, here:
brainly.com/question/1214027
Answer:
Electron geometry- Tetrahedral
Molecular geometry- Bent
Bond angle- <<109.5°
Explanation:
According to the Valence Shell Electron Pair Repulsion (VSEPR) Theory, the shape of a molecule depends on the number of electron pairs present bon the central atom of the molecule. The electron pairs orient themselves as far apart in space as possible to minimize repulsion between electron pairs.
However, the repulsion between all electron pairs is not the same. Lone pairs cause more repulsion around the central atom than bond pairs. Hence lone pairs tend to distort the molecular structure away from that predicted on the basis of Valence Shell Electron Pair Repulsion Theory.
Considering XY2Z2, there are four electron domains, two bond pairs with bonding groups at 180° apart and two lone pairs. Based on VSEPR theory, a tetrahedral shape is expected with a bond angle of about 109°.
The presence of two lone pairs distorts the observed molecular geometry to a bent shape with bond angle <<109°, hence the answer above.
