Based on the types of bonding in the following compunds, explain why you would expect: 1) calcium chloride (CaCl2) to be soluble in water 2) Ethane (CH3CH3) to be insoluble in water
Calcium chloride is a polar bond(ionic). Water is polar. Like dissolves like.
CH3CH3 is a non-polar compound made up of covalent bonds. It isn' very soluble in a polar solvent such as water.
1) Calcium chloride is expected to be soluble in water due to the presence of ionic bonding. In calcium chloride (CaCl2), calcium (Ca) and chlorine (Cl) atoms are held together by ionic bonds. Ionic compounds like calcium chloride have a strong attraction between positively charged ions (cations) and negatively charged ions (anions). Water molecules are polar, with a positive charge on the hydrogen atoms and a negative charge on the oxygen atom. This polarity allows water molecules to surround and interact with the ions in calcium chloride. The positive hydrogen atoms of water molecules are attracted to the negatively charged chloride ions (Cl-), while the negative oxygen atom of water is attracted to the positively charged calcium ion (Ca2+). These interactions lead to dissolution, resulting in calcium chloride dissolving in water.
2) Ethane (CH3CH3) is expected to be insoluble in water due to the presence of covalent bonding. In ethane, the carbon (C) and hydrogen (H) atoms are held together by covalent bonds. Covalent compounds like ethane consist of atoms sharing electrons rather than transferring them like in ionic bonding. Water molecules, on the other hand, are polar and can form hydrogen bonds with other polar molecules or ions. In the case of ethane, there are no significant charges present that would allow strong interactions with water molecules. Since the intermolecular forces between ethane molecules are relatively weak compared to the strong hydrogen bonding in water, the water molecules are unable to effectively break apart and surround the ethane molecules, resulting in insolubility.
To determine why calcium chloride (CaCl2) is soluble in water and why ethane (CH3CH3) is insoluble in water, we need to consider the types of chemical bonding present in each compound.
1) Calcium chloride (CaCl2):
In calcium chloride, there is an ionic bond between the calcium ion (Ca2+) and the chloride ions (Cl-). Ionic bonding occurs when there is a transfer of electrons from one atom to another, resulting in the formation of charged ions. In this case, calcium loses two electrons and becomes a cation with a +2 charge, while each chloride atom gains one electron and becomes an anion with a -1 charge.
Water (H2O) is a polar molecule, meaning it has a slight positive charge on one end (hydrogen atoms) and a slight negative charge on the other end (oxygen atom). The positive end of water molecules attracts negatively charged anions (chloride ions), while the negative end attracts positively charged cations (calcium ion). This attraction between the polar water molecules and the oppositely charged ions overcomes the ionic bond holding calcium chloride together. As a result, the ionic compound easily dissociates in water, with water molecules surrounding and separating the individual calcium and chloride ions, leading to the compound's solubility.
2) Ethane (CH3CH3):
In ethane, there are only covalent bonds between the carbon (C) and hydrogen (H) atoms. Covalent bonding occurs when atoms share electrons to achieve a stable electron configuration. Ethane consists of two carbon atoms bonded to each other with all the hydrogen atoms bonded to the carbon atoms.
Water, being a polar molecule, is capable of forming hydrogen bonds with other polar substances, such as itself or other polar molecules. However, ethane is a nonpolar molecule because the shared electrons in the covalent bonds are evenly distributed between the carbon and hydrogen atoms, resulting in no significant charge separation. Since ethane lacks charged regions that can interact with the polar water molecules via hydrogen bonding, it is considered insoluble in water.
In summary, calcium chloride is soluble in water due to the presence of ionic bonding, which allows dissociation of the compound's ions in water, while ethane is insoluble in water because it lacks the polar nature required for interaction with the polar water molecules.