Hello,
Your questions states:
During a change of state, the temperature of a substance _____?
In which you gave us some choices:
A. decreases if the arrangement of particles in the substance changes.
B. remains constant until the change of state is complete.
C. increases if the kinetic energy of the particles in the substance increases.
D. increases during melting and vaporization and decreases during freezing and condensation.
Your answer would be:
B. remains constant until the change of state is complete.
Your explanation/Reasoning:
It absorbs the energy, then after the phase changes it then increases the temperature all over again.
Have a nice day:)
Hope this helps!
~Rendorforestmusic
It would take 147 hours for 320 g of the sample to decay to 2.5 grams from the information provided.
Radioactivity refers to the decay of a nucleus leading to the spontaneous emission of radiation. The half life of a radioactive nucleus refers to the time required for the nucleus to decay to half of its initial amount.
Looking at the table, we can see that the initial mass of radioactive material present is 186 grams, within 21 hours, the radioactive substance decayed to half of its initial mass (93 g). Hence, the half life is 21 hours.
Using the formula;
k = 0.693/t1/2
k = 0.693/21 hours = 0.033 hr-1
Using;
N=Noe^-kt
N = mass of radioactive sample at time t
No = mass of radioactive sample initially present
k = decay constant
t = time taken
Substituting values;
2.5/320= e^- 0.033 t
0.0078 = e^- 0.033 t
ln (0.0078) = 0.033 t
t = ln (0.0078)/-0.033
t = 147 hours
Learn more: brainly.com/question/6111443
