The water cycle renews water supplies by moving water from the oceans, as freshwater, to land
Answer:
C. kilojoules
Explanation:
The bond energy needed to break or create bonds is measured in units called kilojoules.
Bond energy is a form of enthalpy change of a reaction or physical change. The bond energy is the heat content of a covalent bond formed from its constituent elements in the gas phase.
The bond energy is the same in value as the bond dissociation energy and its unit is given in kilojoules.
Answer:
Ca + Pb(NO3)2 → Pb + Ca(NO3)2
Explanation:
This is an oxidation-reduction (redox) reaction:
PbII + 2 e- → Pb0
(reduction)
Ca0 - 2 e- → CaII
(oxidation)
Pb(NO3)2 is an oxidizing agent, Ca is a reducing agent.
Answer: 1145.8 years
Explanation:
Half-life of carbon-14 = 5720 years
First we have to calculate the rate constant, we use the formula :


Now we have to calculate the age of the sample:
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = age of sample = ?
a = let initial amount of the reactant = 100 g
x = amount decayed = 75 g
a - x = amount left after decay process = 100 - 75 = 25g
Now put all the given values in above equation, we get


Answer:
C because 77.0 CsF
Explanation:
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