It would take 147 hours for 320 g of the sample to decay to 2.5 grams from the information provided.
Radioactivity refers to the decay of a nucleus leading to the spontaneous emission of radiation. The half life of a radioactive nucleus refers to the time required for the nucleus to decay to half of its initial amount.
Looking at the table, we can see that the initial mass of radioactive material present is 186 grams, within 21 hours, the radioactive substance decayed to half of its initial mass (93 g). Hence, the half life is 21 hours.
Using the formula;
k = 0.693/t1/2
k = 0.693/21 hours = 0.033 hr-1
Using;
N=Noe^-kt
N = mass of radioactive sample at time t
No = mass of radioactive sample initially present
k = decay constant
t = time taken
Substituting values;
2.5/320= e^- 0.033 t
0.0078 = e^- 0.033 t
ln (0.0078) = 0.033 t
t = ln (0.0078)/-0.033
t = 147 hours
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N=m(g)/m.wt
n=85/12(1)+16(2) =1.93 moles
The option which accurately defines kinetic energy from the choices above is:
the energy an object has because of its motion
The correct answer choice is option c
In order words, kinetic energy is that type of energy which a body or an object posess due to its relative motion.
<h3>What is energy?</h3>
Energy can simply be defined as the capacity of doing work.
Energy is a derived quantity; meaning that it is obtained from the combination of fundamental quantities.
The unit of energy joules.
Other examples of derived quantities just like energy too are:
- Volume
- Speed
- Acceleration
- Density.
- Upthrust
- Momentum
- Momentum
- Power
- Pressure
- Force
Below are some few forms of energy; these are:
- Kinetic energy
- Potential energy
- Mechanical energy
- Solar energy
- Light energy
- Chemical energy
So therefore, the option which accurately defines kinetic energy from the choices above is:
the energy an object has because of its motion
Learn more about energy:
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Answer: The correct name for the compound 
is, Dicarbon triiodide.
Explanation:
is a covalent compound because in this compound the sharing of electrons takes place between carbon and iodine.. Both the elements are non-metals. Hence, it will form covalent bond.
The naming of covalent compound is given by:
The less electronegative element is written first.
The more electronegative element is written second. Then a suffix is added with it. The suffix added is '-ide'.
If atoms of an element is greater than 1, then prefixes are added which are 'mono' for 1 atom, 'di' for 2 atoms, 'tri' for 3 atoms and so on.
Hence, the correct name for the compound is, Dicarbon triiodide..
It starts with a cation and ends with a nonmetal anion. To recap, cations are your positively charged elements and anions are negatively change and usually with the ending “ide”. For example, potassium a metal and chlorine a nonmetal (KCl) would form the word potassium chloride.
