Which of the following is the best hypothesis? O A. Tearing a piece of paper is an example of a physical change.
B. Physical changes are much less interesting to watch than
chemical changes.
C. Some chemical reactions absorb heat, and others release heat.
D. If sodium carbonate is added to vinegar, the reaction will absorb
heat.

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.

The missing component to the table to the right or indicated with orange letters complete the table by filling in the corresponding numbers or symbols

Select all that apply. using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 (s) pb+2(aq) + 2cl -(aq). the concentration of the products yield a ksp of 2.1 x 10-2: