List all the prime numbers between 100 to 120 and work out the product of the largest and the smallest prime numbers. Classify 1, 2 and sqrt(5) as rational or irrational numbers.

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
The prime numbers between 100 and 120 are:

Smallest prime number = 101
Largest prime number = 113

Product = $101 \times 113$

The product of the largest and smallest prime numbers is $\boxed{11413}$.

A rational number can be expressed as a fraction $\frac{p}{q}$ where $p$ and $q$ are integers and $q \neq 0$.
An irrational number cannot be expressed as a simple fraction; its decimal representation is non-terminating and non-repeating.

1 can be written as $\frac{1}{1}$. Therefore, 1 is a rational number.

2 can be written as $\frac{2}{1}$. Therefore, 2 is a rational number.

Since 5 is not a perfect square, $\sqrt{5}$ cannot be expressed as a simple fraction. Its decimal representation is non-terminating and non-repeating (2.23606...). Therefore, $\sqrt{5}$ is an irrational number.

If the total journey takes 5 hours, then in 1 hour, the train covers $\frac{1}{5}$ of the journey.

Looking up the reciprocal of 5 in a reciprocal table gives:

The fraction of the journey covered in 1 hour is $\boxed{0.2}$.

From reciprocal tables:
$\frac{1}{9.81} \approx 0.1019$
To find $\frac{1}{0.981}$, we can use the relationship $\frac{1}{0.981} = \frac{1}{9.81 \times 10^{-1}} = 10 \times \frac{1}{9.81}$.
So, $\frac{1}{0.981} \approx 10 \times 0.1019 = 1.019$

The evaluated value is $\boxed{4.1779}$.

$256^{\frac{1}{4}} = \sqrt[4]{256}$
Since $4 \times 4 \times 4 \times 4 = 256$, we have $\sqrt[4]{256} = 4$.

$81^{\frac{1}{4}} = \sqrt[4]{81}$
Since $3 \times 3 \times 3 \times 3 = 81$, we have $\sqrt[4]{81} = 3$.

The result is $\boxed*{\frac{4}{3}*}$.