Density is defined as the "mass per unit volume" of an object.
Thus, for an object weighing 100 grams with a volume of 100 milliliters, the density calculates to 100 grams / 100 ml.
When weighing the object, if there is water on the scale's surface, it will contribute additional weight, making the object seem heavier than its actual mass. Consequently, you might mistakenly conclude that the density is GREATER than it truly is.
For instance, if there were 5 ml of water on the scale, with water's density being 1 gram per milliliter (1 g/ml), it would add 5 grams to the object's weight. Using the previous example, the object's mass appears as 105 grams instead of 100 grams. Thus, you would calculate:
density = mass / volume
density = 105 grams / 100 ml
density = 1.05 g/ml
Thus, the effect on density would be to misleadingly suggest it is greater.
I hope this is helpful!
Best of luck
present in 7.5 g of 
equals 3.0 g.