The mass of a 50-ml volumetric flask is 40.638 g. after adding 15.0 ml of 95% ethanol and adding enough water to complete the volume to 50.00 ml, the flask weighed 88.219 g. what is the density of the mixture?

Answer

0.9516 grams / mL (50.00 has 4 sig digs.)

Remark

You have a couple of extraneous numbers there. You don't care about anything except the mass of the flask +  water/alcohol mixture  (88.219 grams). and the mass of the flask (40.638 grams)

Formulas

Solution

mass water/alcohol mixture = 88.219 - 40.638 = 47.581

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.