Which of the following statements is true? a) The rate constant does not depend on the activation energy for a reaction where the products are lower than the reactants. b) A catalyst raises the activation energy of a reaction. c) Rate constants are temperature dependent.

Rate constants are temperature dependent.

Explanation:

Reaction rate is used to quantify the rate of chemical reaction. There is a relationship between the reaction rate and the half-life of the reaction and the Gibbs free energy of activation, and the reaction rate is temperature dependent according to the equation.

For a reaction shown below

a A + b B ⇒ c C

The rate of reaction of the reaction is given by

where k(T) is the reaction constant, which is seen to be dependent on the temperature of the reaction.

Also, k(T) is numerically equal to

where

r = reaction rate

A = pre exponential factor

= Activation energy

R = gas constant

T = temperature

and m and n are experimentally determined partial orders in [A] and [B]

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3