Radiation can cause long-term problems once it enters the environment.

How does a catalyst influence a chemical reaction.

UNO [17]

Answer: C.It provides an alternative energy pathway for the reaction to proceed.

Explanation:

Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and more molecules convert to products.

Thus catalyst speeds up the reaction and does not increase the total amount of product formed.

The catalyst itself does not take part in the chemical reaction and is regenerated as such at the end.

3 0

3 years ago

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The rate at which a certain Australian tree cricket chirps is 194/min at 28°C, but only 47.6/min at 5°C, From these data calcula

uysha [10]

Answer: The energy of activation for the chirping process is 283.911 kJ/mol

Explanation:

According to the Arrhenius equation,

$K=A\times e^{\frac{-Ea}{RT}}$

The expression used with catalyst and without catalyst is,

$\log (\frac{K_2}{K_1})=\frac{Ea}{2.303\times R}[\frac{1}{T_1}-\frac{1}{T_2}]$

where,

$K_2$ = rate of reaction at $28^0C$ = 194/min

$K_1$ = rate of reaction at $5^0C$ = 47.6 /min

$Ea$ = activation energy

R = gas constant = 8.314 J/Kmol

tex]T_1[/tex] = initial temperature = $5^oC=273+5=278K$

tex]T_1[/tex] = final temperature = $28^oC=273+28=301K$

Now put all the given values in this formula, we get

$\frac{194}{47.6}=\frac{E_a}{2.303\times 8.314}[\frac{1}{278}-\frac{1}{301}]$

${E_a}=283911J/mol=283.911kJ/mol$

Thus the energy of activation for the chirping process is 283.911 kJ/mol

8 0

3 years ago

Compare Boyle's law, Charles's law, and Avogadro's law. a. What remains constant in each law? b. What are the variables in each

zavuch27 [327]

Answer:

a)

In Boyle's Law, the variable that remains constant is the absolute temperature of the gas.

In Charle's Law, the variable that remains constant is the pressure of the gas.

In Avogadro's Law, the variables that remain constant are pressure and temperature of the gas.

b)

In Boyle's Law, the variables involved are pressure and volume: the law states that for a fixed mass of ideal gas at constant temperature, the pressure of the gas is inversely proportional to the volume:

$p\propto \frac{1}{V}$

where p is the pressure of the gas and V the volume.

In Charle's Law, the variables involved are volume and temperature: the law states that for a fixed mass of ideal gas at constant pressure, the volume of the gas is directly proportional to the temperature:

$V\propto T$

where V is the volume of the gas and T the temperature.

In Avogadro's Law, the variables involved are the volume and the number of moles: the law states that for an ideal gas kept at constant pressure and temperature, the volume of the gas is directly proportional to the number of moles:

$V\propto n$

Where V is the volume of the gas and n the number of moles.

c)

See the graphs of the three Laws in attachment:

- First graph: Boyle's Law, which shows that the pressure of the gas is inversely proportional to the volume

- Second Graph: Charle's Law, which shows that the volume of the gas is directly proportional to the absolute temperature

- Third graph: Avogadro's Law, which shows that the volume of the gas is directly proportional to the number of moles of the gas

d)

Here we want to re-write the three laws by making V the subject.

For Boyle's law, we get:

$V\propto \frac{1}{p}$

For Charle's Law, we get:

$V\propto T$

For Avogadro's Law, we get:

$V\propto n$

Therefore, we see that the two laws that show a direct proportionality are Charle's Law and Avogadro's Law, while Boyle's Law shows an inverse proportionality between the two variables.