A. solutions and colloids
Answer:- The formula 
tells us that one formula unit of this compound is composed of one calcium atom, two nitrogen atoms, and six oxygen atoms.
Explanations:- Subscripts tell us about the number of atoms of the element for which they are used. For example, here the subscript of Ca is one, it means there is one calcium atom in the given one formula unit.
When we have subscripts inside and outside the parenthesis then they are multiplied and the outside subscript is considered for all the atoms present inside the parenthesis.
Here, for the given chemical formula, the subscript of N is 1 and the subscript present outside is 2. So, 1 x 2 = 2 and for oxygen, 3 x 2 = 6
So, we have one calcium atom, two nitrogen atoms and six oxygen atoms for one formula unit of given compound.
Answer:
C9H13N
Explanation:
Since there is no common factor besides 1, the formula is already the empirical formula for this compound.
Answer:
dipole-dipole forces, ion-dipole forces, higher molar mass, hydrogen bonding, stronger intermolecular forces
Explanation:
<em>1. H₂S and H₂Se exhibit the following intermolecular forces: </em><em>dipole-dipole forces </em><em>and </em><em>ion-dipole forces</em><em>.</em> These molecules have a bent geometry, thus, a dipolar moment which makes them dipoles. When they are in the aqueous form they are weak electrolytes whose ions interact with the water dipoles
<em>2. Therefore, when comparing H₂S and H₂Se the one with a </em><em>higher molar mass</em><em> has a higher boiling point.</em> In this case, H₂Se has a higher boiling point than H₂S due to its higher molar mass.
<em>3. The strongest intermolecular force exhibited by H₂O is </em><em>hydrogen bonding</em><em>. </em>This is a specially strong dipole-dipole interaction in which the positive density charge on the hydrogens is attracted to the negative density charge on the oxygen.
<em>4. Therefore, when comparing H₂Se and H₂O the one with </em><em>stronger intermolecular forces</em><em> has a higher boiling point. </em>That's why the boiling point of H₂O is much higher than the boiling point of H₂Se.
Density is equal to mass divided by volume so the densest object will be the object that has the largest mass in the smallest area.
In this case object A is the densest with a density of 10g/cm^3.
I hope this helps. Let me know if anything is unclear.
