Using a triple beam balance and a graduated cylinder, a student collected data on a sample of an element:Mass of sample = 18.9 gVolume of water = 30.0 mLVolume of water and sample = 35.0 mL using SigFig Rules *

The question is incomplete; the complete question is;

Using a triple beam balance and a graduated cylinder, a student collected data on a sample of an element:

Mass of sample = 18.9 g

Volume of water = 30.0 mL

Volume of water and sample = 35.0 mL

Calculate the density of the sample using sig figs.

3.8 g/mL

Explanation:

Mass of sample = 18.9 g

Volume of water = 30.0 mL

Volume of water and sample = 35.0 mL

Volume of the sample = 35.0 mL – 30.0 mL = 5.0 mL

D = m/v

D = 18.9 g / 5.0 mL =3.8 g/mL

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.