To solve this we assume
that the gas is an ideal gas. Then, we can use the ideal gas equation which is
expressed as PV = nRT. At a constant temperature and number of moles of the gas
the product of PV is equal to some constant. At another set of condition of
temperature, the constant is still the same. Calculations are as follows:
P1V1 =P2V2
P2 = P1 x V1 / V2
P2 = 2.0 x 1.5 / 3
<span>P2 = 1 atm</span>
Explanation:
Molarity is defined as number of moles per liter of solution.
Mathematically, molarity = 
It is given that molarity is 0.0800 M and volume is 50.00 mL or 0.05 L.
molarity = 
0.0800 M = 
no. of moles = 1.6 mol
Therefore, molar mass of cupric sulfate pentahydrate is 249.68 g/mol. So, calculate the mass as follows.
No. of moles = 
mass in grams = 
= 
= 399.488 g
Thus, we can conclude that 399.488 g of cupric sulfate pentahydrate are needed to prepare 50.00 mL of 0.0800M CuSO4× 5H2O.
Answer:

Explanation:
Hello,
In this case, given the described concept regarding the Avogadro's number, we can easily notice that 27.0 g of aluminium foil has 6.022x10²³ atoms as shown below based on the mass-mole-particles relationship:

Notice this is backed up by the fact that aluminium molar mass if 27.0 g/mol.
Best regards.