Answer:
Down arrow:
-a car comes to a stop when a traffic light turns red
Up arrow:
-race car accelerates when a race begins
Circle:
-car driving 45 mile per hour down straight road
Explanation:
and i think the car going around a bend would be an up arrow
12.5%
Three half lives pass. 50% -> 25% -> 12.5%
Answer: 
for the reaction 
is -108kJ
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
![\Delta H=[n\times B.E_{reactants}]-[n\times B.E{products}]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Bn%5Ctimes%20B.E_%7Breactants%7D%5D-%5Bn%5Ctimes%20B.E%7Bproducts%7D%5D)
where, n = number of moles
Now put all the given values in this expression, we get
![\Delta H=[1\times B.E_{Cl_2}+1\times B.E_{F_2}]-[2\times B.E_{ClF}]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B1%5Ctimes%20B.E_%7BCl_2%7D%2B1%5Ctimes%20B.E_%7BF_2%7D%5D-%5B2%5Ctimes%20B.E_%7BClF%7D%5D)
![\Delta H=[(1\times 243)+(1\times 159)]-[2\times 255]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%281%5Ctimes%20243%29%2B%281%5Ctimes%20159%29%5D-%5B2%5Ctimes%20255%5D)
Thus for the reaction is -108kJ
Answer:
b is constant
Explanation:
The half-life of a radioisotope is constant throughout its life cycle.
Half-life is the time taken for half of the radioactive nuclei to disintegrate.
Every radionuclide has its characteristic half-life and it is independent of the number of radioactive atoms.
- The half-life does not depend on any variable. It is an inherent property of a radioactive isotope.
- The shorter the half-life, the faster a radionuclide decays.
- Nuclides with a long half life are fairly stable for a long period of time.
- The decay of a radioactive element is usually characterized by its half-life.
Therefore, the most ideal statement about half-life is that it is constant.
