All the following are signs of a chemical reaction, except

a. a change in color or odor.
b. a release of gas.
c. a change of state.
d. a change in energy.

Select the correct answer how does the heat content of the reaction change in the process of photosynthesis when a glucose molecule is formed? ca the value of is negative the value of qis positive the value of a remains constant the value of a decreases the value of equals zero e

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.