PHY S 100 Lesson 20
In order for a chemical reaction to occur
?
products
the end results of a chemical reaction
Which of the following is the best description of activation energy?
the energy that must be put into a system before a reaction can take place.
reactants
the starting materials before a chemical reaction
In the chemical equation C6H12O6 + 3O2 ⇒ 3CO2 + 6H2O, how many oxygen atoms are on the right side of the equation?
12
In the equation C2H4 + 3O2 = ? CO2 + 2H2O, how many CO2 molecules are needed to balance the equation?
2
In which of the following processes is the end product more ordered than the reactants? (In which process does entropy decrease in the system?)
2H2 (gas) + O2 (gas) = 2 H2O (gas)
Which of the equations below is balanced correctly?
CH4 +2O2 ⇒ CO2 + 2H2O
Chemical bond rule
If the new molecular orbital is lower in an energy well and overall entropy increases, electrons go to this state and they can't get out—a chemical bond is formed. This chemical bond is stable unless energy is added.
anti-bonding orbital
The second type of orbital is called this because there is a low probability of electrons being between the two atoms
Energy and entropy are both involved in chemical reactions.
True
activation entropy
reactions will only take place when the reactants are lined up in a particular orientation.
A very fast reaction has a very high activation energy.
False
Molecular orbitals are the same shape as atomic orbitals.
False
How does a catalyst affect a reaction?
It lowers the activation energy.
bonding orbital
The first molecular orbital, a chemical bond can occur with this type of orbital and the electrons have a high probability of being between the two atoms
molecular orbitals
The orbital patterns which formed standing waves for a single nucleus do not form standing waves for this new situation.
These graphs show energy as a function of time for several different reactions. Which of the reactions shown below would end up absorbing energy from the surroundings?
graph goes up slightly but never returns all the way down to where the energy line is
In a bonding orbital between two atoms, where is the electron density the highest? (Where do you have the highest probability of detecting an electron?)
in between the two atoms