اللي يقدر يفيدني بسؤالين فالكيمياء يدخل .؟.

[دكتورة.]

The following procedure was used to determine the volume of a flask.
The flask was weighted dry and then filled with water. If the masses of empty flask and filled flask were 56.12g and 87.39g,respectively, and the density of water is 0.9976g/cm3, Calculate the volume of the flask in cm3?
A.
56.255 cm3
B.
87.6 cm3
C.
31.345 cm3 *
D.
143.855

هنا ايش سوا جمع الكتله للانبوبه الفارغه والممتلئه ولا طرحها ولا ايش الحكايه .؟.؟

Express 75 Tg as pg
A.
7.5 pg
B.
75 X1024 pg *
C.
0.75 pg
D.
75 X10-24 pg

وهذا ايش الوحدات هذي ؟.؟.؟ وكيف انحلت ؟؟