i need help with these for my chem class

Question

1.)how many atoms of nickel are there in 40.08 moles ni

2.)how many moles of argon are there in 9.80 x 10^25 atoms

3.)How many moles of LIF are there in 60.09g?

4.)how many grams are there in 0.3606 moles of copper?

6.)how many grams of magnesium are there in 6.55 x 10^25 atoms?

7.)how many grams of copper(II) sulfate are there in 396 moles of CuSO4?

 

need it as soon as possible its for school 

Answer 1

Well, I won't do your homework, but will guide you.

1)  There are 6.02x10²³ atoms in 1 mole of anything.  Do the math.

2)  Use the same 6.02x10²³ atoms/mole and calculate moles of Ar.

3)  1 mole of LiF = (6.941 g + 18.998 g) = 25.929 g.  Calculate moles in 60.09 g.

4)  1 mole of copper = 63.546 g.  Calculate grams in 0.3606 moles.

6)  Using 6.02x10²³ atoms/mole, find # moles in 6.55x10²⁵ atoms. Then using 24.305 g/mole Mg, find grams Mg.

7)  Find molar mass of CuSO4 by adding atomic mass Cu + S + 4 O. Then multiply that by 396 moles to get grams.