The number of years required for 1/4 cobalt-60 to remain after decay is calculated as follows
after one half life 1/2 of the original mass isotope remains
after another half life 1/4 mass of original mass remains
therefore if one half life is 5.3 years then the years required
= 2 x 5.3years = 10.6 years
Answer:
Mass of water = 41.8 g
Explanation:
Given data:
Mass of water = ?
Change in temperature = 3.0 °C
Specific heat capacity = 4.184 j/g.°C
Heat absorbed = 525 j
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 3.0°C
Now we will put the values in formula.
525 J = m × 4.184 j/g.°C × 3.0°C
525 J = m × 12.552 j/g
m = 525 J/ 12.552 j/g
m = 41.8 g
It's a physical change. A physical change is when an object can return back to it's previous state, etc. If it was a chemical change, the object would not be able to return back to it's previous shape, state or size, etc.
