Suppose a hydrogen-oxygen fuel-cell generator was used to produce electricity for a house. Use the balanced redox reactions and the standard cell potential to predict the volume of hydrogen gas (at STP) required each month to generate the electricity needed for a typical house. Assume the home uses 1400 kWh of electricity per month.

Two changes are described below. a green banana turns yellow and ripens. a layer of rust forms on an iron nail. which statement is true about the two changes? a) both are chemical changes because new substances are formed. b) both are physical changes because only the physical state of the substances change. c) a is a physical change due to a change of state, but b is a chemical change because new molecules are formed. d) a is a chemical change due to a change of state, but b is a physical change because new molecules are formed.