Amap with a scale of 1: 24,000 means that

1:24000

the 1 indicates the actual size of one unit.

24000 is the scale units for the one unit of actual size on the map

for example. if its 1 inch =24000 miles, then every inch of map there is, is 24000 miles.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.