ch 20 unit 3 physical sciencce

In order for a chemical reaction to occur:

Entropy must increase as a result of the reaction

Molecular orbitals are the same shape as atomic orbitals.

false

Energy and entropy are both involved in chemical reactions.

true

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 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.

In which of the following processes is the end product more ordered than the reactants? (In which process does entropy decreases.) Select one: a. 2H2 (gas) + O2 (gas) = 2 H2O (gas) b. 2C8H18 (liquid) + 25O2 (gas) = 16CO2 (gas) + 18H2O(gas) c. C6H12O6 (solid) + 6O2 (gas) = 6CO2 (gas) + 6H2O (liquid) d. 2C7H5N3O6 (solid) = 3N2(gas) + 7CO(gas) + 5H2O(gas) + 7 C(solid) e. NaHCO3(solid) + C2H4O2(liquid)=C2H3NaO2(solid)+ H2O(liquid) + CO2 (gas)

a. 2H2 (gas) + O2 (gas) = 2 H2O (gas)

How does a catalyst affect a reaction?

It lowers the activation energy

What is the best description of activation energy?

The energy that must be put into a system before a reaction can take place.

A very fast reaction has a very high activation energy.

false

What will end of the graph be higher or lower than the beginning energy if the reaction absorbed energy?

it will be higher than the start