The dilution factor for a single dilution is:
#color(blue)(|bar(ul(color(white)(a/a) "DF" = V_f/V_i color(white)(a/a)|)))" "#
If you are doing successive dilutions, the overall dilution factor is the product of each successive dilution factor.
#color(blue)(|bar(ul(color(white)(a/a) "DF" = "DF"_1 × "DF"_2 × "DF"_3 × …color(white)(a/a)|)))" "#
In your example,
Your sample is not a liquid, but it is generally agreed that 1 g of sample has a volume of 1 mL, even if that is not actually the case. You still get convenience and reproducibility.
The overall dilution factor is 5000.
The dilution factor is often used as the denominator of a fraction.
For example, a