Answer:
Check the explanation
Explanation:
AT = A0 e(-T/H)
... where A0 is the starting activity, AT is the activity at some time T, and H is the half-life, in units of T.
Substituting what we know, we get...
0.71 = (1) e(-T/5730)
Solve for T...
loge(0.71) = -T/5730
T = -loge(0.71)(5730)
T = 1962 (conservatively rounded, T = 2000)
similarly for all
for aboriginal charcoal
0.28 = (1) e(-T/5730)
Solve for T...
loge(0.28) = -T/5730
T = -loge(0.28)(5730)
T = 7294 (conservatively rounded, T = 7000)
for mayan headdress
0.89 = (1) e(-T/5730)
Solve for T...
loge(0.89) = -T/5730
T = -loge(0.89)(5730)
T = 667 (conservatively rounded, T = 700)
for neanderthal
0.05 = (1) e(-T/5730)
Solve for T...
loge(0.05) = -T/5730
T = -loge(0.05)(5730)
T = 17165 (conservatively rounded, T = 17000)
Answer:
Near the boiling point of the solvent
Explanation:
The process of recrystallization is hinged on the fact that the amount of solute that can be dissolved by a solvent increases with temperature. The process involves creation of a solution by dissolving a solute in a solvent at or near its boiling point. At the boiling point of the solvent, the solute has a greater solubility in the solvent; not much volume of the hot solvent is required to dissolve the solute.
Before the solution is later cooled, you can now filter out insoluble impurities from the hot solvent. The quantity of the original solute drops appreciably because impurities have been removed. At this lower temperature, the solution becomes saturated and the solute can no longer be held in solution hence it forms pure crystals of solute, which can be recovered.
Recrystallization must be carried out using the proper solvent. The solute must be relatively insoluble in the solvent at room temperature but more soluble in the solvent at elevated temperature.
The water well begin to freeze and turn into soild. why? because the temperature of the the freezer is getting the water bottle cold so when that cold temperature hits that that bottle which has liquid in it so you should know that when liquid is into cold air it well so be soild so when you put the water bottle in the freezer it will be soild.
and also remember gas - liquid - soild gas change to liquid by hot air and liuid change to soild by clod air
hoped i helped
Answer:
The answer to your question is Q = 18702.5 J
Explanation:
Data
mass of water = m = 447 g
Cp = 4.184 J/g°C
Temperature 1 = T1 = 25°C
Temperature 2 = T2 = 35°C
Heat = Q = ? Joules
Process
1.- Write the formula to calculate heat
Q = mCp(T2 - T1)
2.- Substitution
Q = (447)(4.184)(35 - 25)
3.- Simplification
Q = (447)(4.184)(10)
4.- Result
Q = 18702.5 J
The answer is c i need brainlyest plz
