Does data entropy depend on the arrangement of the characters in a file?
Entropy is a property of the source of the data, i.e., of the distribution that the data is drawn from -- not a property of the particular file.  You can't calculate the entropy given a single file.  Instead, you need to know the distribution that file came from.  Or, to put it another way, the entropy is a measure of the process used to generate the particular file, not a measure of one particular file you happened to get from that process; and observing one  output from that process isn't enough to let you calculate the entropy of the process.  So, the question isn't well-formed.

You might be thinking of forming the empirical distribution of characters, then assuming the file came from a memoryless iid source (where each character was drawn independently according to that distribution), and then calculating the entropy under that assumption.  But that assumption doesn't hold for your bigger file, so this isn't a valid way of calculating the actual entropy of the process that was used to generate the bigger file.

To learn more: How to practically measure entropy of a file?, https://en.wikipedia.org/wiki/Entropy_(information_theory).