Answer:
36 years
Explanation:
2 = 16 * (1/2)^n where n is the number of half lives
2/16 = (1/2)^n
1/8 = (1/2)^n
log (1/8) = log (1/2^n)
log(1/8) = n log (1/2)
log ( 1/8 ) / log(1/2) = n = 3 half lives
each half life is 12 years so 3 * 12 = 36 years
Answer:
D - chemical and physical
Explanation:
Only chemical and physical changes can reach the level of dynamic equilibrium. Nuclear reactions cannot reach dynamic equilibrium.
- A system is in dynamic equilibrium when the rate of forward reaction is the same as that of backward reaction in a reversible reaction.
- Nuclear reactions cannot be reversed.
- Dynamic equilibrium is prominent in chemical reactions. It is commonly found that as a reaction occurs, the backward and forward reactions can reach equilibrium levels.
- In physical changes, this can also occur when certain conditions of pressure and temperatures are satisfied.
If there was more water area and less land more animals would adapt to the water life than land. Like for example more evolving fins or even amphibians
just staying in water and no longer needing legs or the things they use for living on the land.
Answer: 406 hours
Explanation:
where Q= quantity of electricity in coloumbs
I = current in amperes = 39.5 A
t= time in seconds = ?
The deposition of copper at cathode is represented by:
Coloumb of electricity deposits 1 mole of copper
i.e. 63.5 g of copper is deposited by = 193000 Coloumb
Thus 19.0 kg or 19000 g of copper is deposited by = 
Coloumb
(1hour=3600s)
Thus it will take 406 hours to plate 19.0 kg of copper onto the cathode if the current passed through the cell is held constant at 39.5 A
