<span>Na2CO3 (aq) + CaCl2H4O2 (aq) = CaCO3 (s) + 2 NaCl (aq) + 2 H2O (l)</span>
The concentration of solution in M or mol/L can be calculated using the following formula:
.... (1)
Here, n is number of moles and V is volume of solution in L.
The molecular formula of potassium sulfate is 
thus, there are 2 moles of potassium in 1 mol of potassium sulfate.
1 mol of potassium will be there in 0.5 mol of potassium sulfate.
Mass of potassium is 4.15 g, molar mass is 39.1 g/mol.
Number of moles can be calculated as follows:
Here, m is mass and M is molar mass
Putting the values,
Thus, number of moles of will be 
.
The volume of solution is 225 mL, converting this into L,
Thus,
Putting the values in equation (1),
Therefore, concentration of potassium sulfate solution is 0.236 M.
Answer:
A. Metallic bond
Explanation:
Think about it: copper and tin are both common metals. That's how we know it's a metallic bond!
Why not B: Covalent bonds are between two nonmetals.
Why not C: Ionic bonds are between a nonmetal and a metal.
Why not D: Paired bond isn't a common phrase in chemistry.
One thing to notice in the question is, we are asked about molecular oxygen that has formula O2 not atomic oxygen O.
As we are asked about molecular oxygen, we will answer the question in terms of number of molecules that are present in 16 grams of molecular oxygen.
To get the number of molecules present in 16 grams of O2, we will use the formula:
No. of molecules = no. of moles x Avogadro's number (NA)----- eq 1)
As we know:
The number of moles = mass/ molar mass of molecule
Here we have been given mass already, 16 grams and the molar mass of O2 is 32 grams.
Putting the values in above formula:
= 16/32
= 0.5 moles
Putting the number of moles and Avogadro's number (6.02 * 10^23) in eq 1
No. of molecules = 0.5 x 6.02 * 10^23
=3.01 x 10^23 molecules
or 301,000,000,000,000,000,000,000 molecules
This means that 16 grams of 3.01 x 10^23 molecules of oxygen.
Hope it helps!
