Which of the following flouride has the highest lattice energy a)NaF b)KF c)CsF d)LiF
1 answer:
Answer:
The correct option is;
d) LiF
Explanation:
The Lattice energy of ionic compounds can be calculated using the modified Coulomb's law as follows;
Where;
Q₁ and Q₂ = The ionic charges
k' = A constant depending on the ionic and valence configuration
r₀ = The distance between the two nucleus
Given the four compounds each of the metallic ions are of the same group (group one) have the same (only one) valence electron, and are combined to the same ion (fluoride ion) such that Q₂, is the same for all compounds, the factor that will influence the lattice energy more will be the r₀
The sizes of the atoms Li, Na, K and Cs increases as arranged as such Li has the least r₀, and therefore LiF the least lattice energy
From chemistry test online, we have;
The lattice energy of LiF = -1045 kJ/mole
The lattice energy of NaF = -924 kJ/mole
The lattice energy of KF = -822 kJ/mole
The lattice energy of CsF = -737 kJ/mole.
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Answer : The solution with pH 8.3 is an alkaline solution.
Explanation: pH is a measure of hydrogen ion concentration; a measure of the acidity or alkalinity of a solution. The pH scale usually ranges from 0 to 14.
Aqueous solutions with a pH less than seven are acidic, acidity increases as the number decreases, 1 being the most acidic. Aqueous solution with a pH greater than seven are basic or alkaline, alkalinity increases as the number increases, 14 being the most alkaline. Aqueous solution with pH = 7.0 is a 'neutral' solution.
1) pH less than 7(pH < 7) , solution is acidic.
2) pH = 7 , solution is neutral.
3) pH greater than 7(pH > 7), solution is alkaline.
In our given question the pH of solution is given as 8.3 , since pH is greater than 7 , so the solution is 'Alkaline solution'.
The name of this hydrocarbon is 2 methyl butane
Hydrocarbons are the simplest carbon compounds because they are composed of carbon and hydrogen atoms.
Hydrocarbons can be differentiated into bonds in the carbon chain:
• Saturated hydrocarbons: all carbon chains are single bonds (alkanes)
• Unsaturated hydrocarbons: the carbon chain has a double bond (alkenes) and a triple bond (alkyne)
Alkanes are saturated hydrocarbons with all carbon bonds being single bonds
General formula:
There are several rules for naming alkanes from IUPAC:
• branch name followed by the name of the main chain
• the main chain is the longest chain that has the most branches
• the branch is named alkyl with the symbol -R, and begins with a number, with the position of the branch getting the smallest number
• more than one branch is given the prefix di, tri, tetra, penta, etc. and in alphabetical order with the smallest number.
If we look at the hydrocarbon structure in the problem then:
- if we calculate the number of atoms C and H obtained: C = 5 atoms, H = 12 atoms so that the molecular formula is C₅H₁₂ so that it is included in the alkane (CnH2n+2)
- the main chain (the longest chain) consists of 4 C atoms (butane)
- there is 1 branch chain, namely methyl (1 C atom, CH₃)
- The branch is placed in position number 2 of the main branch (the smallest number), so the numbering of the chain starts from the left
So the name of this hydrocarbon is 2 methyl butane
Hydrocarbons contain two types of atoms
The IUPAC nomenclature of alkanes
naming structures with IUPAC rules
Name the following compound
Keywords: IUPAC, alkanes, Saturated hydrocarbons, Unsaturated hydrocarbons, alkyl
