#Question id: 54
#Section C (Domain-Specific Knowledge)
About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?
#Question id: 55
#Section C (Domain-Specific Knowledge)
The standard free energy change for the reaction A → B is −15.0 kJ · mol−1. What is the equilibrium constant for the reaction at 25°C?
#Question id: 56
#Section C (Domain-Specific Knowledge)
Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
#Question id: 57
#Section C (Domain-Specific Knowledge)
A(n) ________ has charge but negligible mass, whereas a(n) ________ has mass but no charge.
#Question id: 58
#Section C (Domain-Specific Knowledge)
A covalent chemical bond is one in which ________.
#Question id: 59
#Section C (Domain-Specific Knowledge)
Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?