1. How many atoms are in 2.15 moles of water? *2. How many atoms of copper are in 12.0 grams?
*3. How many moles of NH3 contain 1.75 x 10^24 molecules of?
4. Determine the number of molecules in 16.75 g of H2O ?
5. Find the formula for a hydrate with 48.8% MgSO4 & 51.2% H2O
6. What is the % by mass of C in Pb(C2H3O2)2?
(Questions with stars just don't make sense to me.)

pie chart because it is in percents ( % )

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.