To determine how much more a mineral with a specific gravity of 3.5 would weigh compared to an equal volume of water, we can use the following formula:

Weight of mineral = Specific gravity of mineral x Weight of water

Since the specific gravity of water is 1, the weight of water can be represented as 1.

Therefore, the weight of the mineral = 3.5 x 1 = 3.5 times the weight of water.

So, a mineral with a specific gravity of 3.5 would be expected to weigh 3.5 times as much as an equal volume of water.