Answer: a. 79.6 s
b. 44.3 s
c. 191 s
Explanation:
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
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for completion of 32% of reaction
c) for completion of 81 % of reaction
Answer:
A. The balloons will increase to twice their original volume.
Explanation:
Boyle's law states that the pressure exerted on a gas is inversely proportional to the volume occupied by the gas at constant temperature. That is:
P ∝ 1/V
P = k/V
PV = k (constant)
P = pressure, V = volume.
Let the initial pressure of the balloon be P, i.e. , initial volume be V, i.e.
. The pressure is then halved, i.e.
Therefore the balloon volume will increase to twice their original volume.
Answer:
.
Explanation:
Carbon and hydrogen are the only two elements in a hydrocarbon. When a hydrocarbon combusts completely in excess oxygen, the products would be and
. The
and
would come from the hydrocarbon, while the
atoms would come from oxygen.
Look up the relative atomic mass of these three elements on a modern periodic table:
Calculate the molar mass of and
:
.
Calculate the number of moles of molecules in
of
:
.
Similarly, calculate the number of moles of molecules in
of
:
.
Note that there is one carbon atom in every molecule. Approximately
of
molecules would correspond to the same number of
atoms. That is:
.
On the other hand, there are two hydrogen atoms in every molecule. approximately
of
molecules would correspond to twice as many
atoms. That is:
.
The ratio between the two is: .
The empirical formula of a compound gives the smallest whole-number ratio between the elements. For this hydrocarbon, the empirical formula would be .