Answer:
C
Explanation:
I am not 100% sure tho correct me if I'm wrong pls:/
Answer:
D
Explanation:
At constant volume, the heat of reaction is equal to the change in the internal energy of the system. ... Most chemical reactions occur at constant pressure, so enthalpy is more often used to measure heats of reaction than internal energy.
Answer: Read Explanation
Explanation: Index fossils are useful because they tell the relative ages of the rock layers in which they occur. Geologists use particular types of organisms, such as trilobites, as index fossils.
The question can be changed into a new form:
Which element has the most negative electron affinity, or attraction for electrons? halogens have the highest electron affinities, and thus are more attracted to the electrons in the Hydrogen atom than any element in their respective periods.
In this case all the following choices are in the same period, thus Cl or Chlorine is the answer as it is a halogen.
