Answer:
. CuO
Explanation:
Since oxygen also has -2 the valency will cancel out the +2 on Cu leaving CuO
A. Protons neutrons and electrons.
Haha those three make up a simple Atom.
Answer: 4.22 grams of solute is there in 278 ml of 0.038 M 
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
where,
n = moles of solute
= volume of solution in L
Now put all the given values in the formula of molality, we get

mass of
= 
Thus 4.22 grams of solute is there in 278 ml of 0.038 M 
We can rearrange the ideal gas equation:
PV = nRT, where n is the number of moles equivalent to:
n = mass / Mr
PV = mRT/Mr
m/V = PMr/RT
density = PMr / RT; where Mr and R are constant.