Most heterogeneous reactions are slower than similar homogeneous reactions.  Which of the following best explains why?

For a chemical reaction, the rate constant at 250.0 °C is 0.00383 s‑1, and the activation energy is        22.40 kJ mol‑1.  Calculate the value of the rate constant at 335.0 °C.

What is the ecological name for the transitional zone between two well defined communities?

What of the following statements is TRUE about mutualistic relationships

The reaction of substance A with substance C was carefully studied under conditions where the [C] remained essentially constant.  The graphs of [A] vs. time and that of ln[A] vs. time both gave curves, but the graph of 1/[A] vs. time gave a straight line. The reaction is therefore _______ order with respect to A.

What mechanism explains the long term coexistence of two species that compete for the same resources?

Aphids feed on the sap of many herbaceous plants. They are generally harmful , transmit diseases and limit growth, but do not kill the plant. What type of ecological interaction best describes the relation between the aphid and the plant?

Which type of dose-response relationship represents radiation-induced leukemia and genetic effects?

A biologic reaction is produced by 4 Gyt of a test radiation. It takes 16 Gyt of 250-kVp x-rays to produce the same biologic reaction. What is the relative biologic effectiveness (RBE) of the test radiation?

Possible responses to irradiation in utero include 1. spontaneous abortion 2. congenital anomalies 3. childhood malignancies