This question id from IB exam,please help!
1)Which compound has the highest lattice enthalpy?
A. CaO
B. CaS
C. LiF
D. LiI
Explain the reason ?
Lattice energy is higher for higher charge on the ions; therefore, you would pick CaO or CaS as higher than LiF and LiI. Then the larger size of the ions decreases lattice energy; therefore, LiI is lower than LiF and CaS should be lower than CaO. I would go with CaO as having the highest lattice energy.
Thanks for helping me DrBob222.I am studying IB program and I have many questions and problems I do not understand about chemistry.I will post them later.I hope you can follow and help me.I am so grateful.Thank you so much ^_^
Thanks for helping me DrBob222.I am studying IB program and I have many questions and problems I do not understand about chemistry.I will post them later.I hope you can follow and help me.I am so grateful.Thank you so much ^_^
Well, let me put on my scientific clown nose and try to answer your question!
When it comes to lattice enthalpy, we're talking about the energy released when gaseous ions come together to form a solid ionic compound. This energy is influenced by the size and charge of the ions involved.
Now, let's look at the options:
A) CaO - That's "calcium oxide" for those not in the chemical know. Calcium has a +2 charge and oxygen has a -2 charge. It's like a chemical balancing act!
B) CaS - This time it's "calcium sulfide." Calcium still has a +2 charge, but sulfur has a -2 charge instead of oxygen.
C) LiF - Here we have "lithium fluoride." Lithium has a +1 charge and fluorine has a -1 charge.
D) LiI - Last but not least, "lithium iodide." Lithium is still +1, but iodine throws in a -1 charge.
Now, when it comes to lattice enthalpy, the smaller the ions and the higher their charge, the stronger the attraction between them. So, the answer is C) LiF because lithium and fluorine are smaller and have higher charges compared to the other options.
Remember, in the world of chemistry, size and charge can make all the difference!
To determine which compound has the highest lattice enthalpy, we need to consider the factors that affect lattice enthalpy and compare the values for each compound.
Lattice enthalpy is a measure of the energy released when gaseous ions are combined to form a solid ionic compound. It depends on the charges of the ions and the sizes of the ions.
The general rule is that the higher the charges and the smaller the ion sizes, the higher the lattice enthalpy.
Let's compare the compounds one by one:
A. CaO: Calcium oxide consists of Ca2+ cations and O2- anions. Calcium ions have a charge of +2, and oxygen ions have a charge of -2. Both ions are relatively small in size. Therefore, the lattice enthalpy of CaO is high.
B. CaS: Calcium sulfide contains Ca2+ cations and S2- anions. Calcium has a charge of +2, and sulfur has a charge of -2. The sizes of both ions are similar to those in CaO. Hence, the lattice enthalpy of CaS is also high.
C. LiF: Lithium fluoride is made up of Li+ cations and F- anions. Lithium has a charge of +1, and fluorine has a charge of -1. The size of Li+ is smaller than that of Ca2+, resulting in a higher lattice enthalpy for LiF compared to CaO and CaS.
D. LiI: Lithium iodide consists of Li+ cations and I- anions. Lithium has a charge of +1, and iodine has a charge of -1. Similar to LiF, the size of Li+ is smaller than that of Ca2+, giving LiI a higher lattice enthalpy than CaO and CaS.
So, based on the reasoning, the compound with the highest lattice enthalpy is LiF (Option C).