Answer:
See explanation below.
Explanation:
Both carbon and silicon are members of group 4A(now group 14) i n the periodic table. Carbon is the first member of the group. CO2 is a gas while SiO2 is a solid. In SiO2, there are single bonds between silicon and oxygen and the geometry around the central atom is tetrahedral while in CO2, there are double carbon-oxygen bonds and the geometry around the central atom is linear. CO2 molecules are discrete and contain only weak vanderwaals forces.
Again, silicon bonds to oxygen via its 3p orbital while carbon bonds to oxygen via a 2p orbital. As a result of this, there will be less overlap between the pi orbitals of silicon and that of oxygen. This is why tetrahedral bonds are formed with oxygen leading to a covalent network solid rather than the formation of a silicon-oxygen pi bond. A covalent network solid is known to be made up of a network of atoms of the same or different elements connected to each other continuously throughout the structure by covalent bonds.
In SiO2, each silicon atom is surrounded by four oxygen atoms. Each corner is shared with another tetrahedron. SiO2 forms an infinite three dimensional structure and melts at a very high temperature.
Carbon and oxygen form a molecular compound CO2 with weaker covalent bonds, while silicon and oxygen form a covalent network solid SiO2 with stronger, three-dimensional covalent bonds.
The difference in bonding between carbon and oxygen compared to silicon and oxygen is due to the different nature of their chemical bonds. In the case of carbon and oxygen, they form a molecular compound CO2, where carbon and oxygen atoms share electrons to form covalent bonds. This is because carbon and oxygen have similar electronegativities, so they can share electrons equally. The covalent bonds in CO2 are relatively weak, allowing the compound to exist as a gas at room temperature and pressure.
On the other hand, silicon and oxygen form a covalent network solid with the formula unit SiO2, known as quartz. In this case, silicon and oxygen atoms are covalently bonded in a three-dimensional network structure, where each silicon atom is bonded to four oxygen atoms and each oxygen atom is bonded to two silicon atoms. This network structure gives SiO2 its high melting point and hardness, making it a solid at room temperature and pressure.
In summary, the difference in bonding between carbon and oxygen compared to silicon and oxygen is that carbon and oxygen form a molecular compound with weaker covalent bonds, while silicon and oxygen form a covalent network solid with stronger, three-dimensional covalent bonds.
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Answer:
Baking, microwave, heating system for your house, water boiler, fridge.
The substance which has definite composition with definite physical and chemical properties is said to be pure substance. These substances are not separated by the different physical techniques such as filtration, distillation, evaporation etc.
The clear water pumped from a deep aquifer is a pure substance because water is a pure compound which consist of constant single type of atoms or group of atoms and water has specific value of boiling and melting point. Water is also not separated into units or constituents by physical technique.
Hence, clear water pumped from a deep aquifer is a pure substance.
Answer:
Yes
Explanation:
As pure substances are substances that are formed directly by elements and water is directly formed by the union of two elements which is Oxygen and hydrogen, H2O is the formula and that is a pure substance as it is conformed mainly by only these two elements, so the question would be Yes, clear water pumped from a deep aquifer is a pure substance.
Consider the titration of a 17.2 mL sample of 0.128 M HC2H3O2 with 0.155 M NaOH. Ka(HC2H3O2) = 1.8x10-5 Determine the pH at 0.46 mL of added base.
Answer:
1. pH = 2,82
2. 3,20mL of 1,135M NaOH
3. pH = 3,25
Explanation:
The buffer of acetic acid (HC₂H₃O₂) is:
HC₂H₃O₂ ⇄ H⁺ + C₂H₃O₂⁻
The reaction of HC₂H₃O₂ with NaOH produce:
HC₂H₃O₂ + NaOH → C₂H₃O₂⁻ + Na⁺ + H₂O
And ka is defined as:
ka = [H⁺] [C₂H₃O₂⁻] / [HC₂H₃O₂] = 1,8x10⁻⁵ (1)
1. When in the solution you have just 0,13M HC₂H₃O₂ the concentrations in equilibrium will be:
[H⁺] = x
[C₂H₃O₂⁻] = x
[HC₂H₃O₂] = 0,13 - x
Replacing in (1)
[x] [x] / [0,13-x] = 1,8x10⁻⁵
x² = 2,34x10⁻⁶ - 1,8x10⁻⁵x
x² - 2,34x10⁻⁶ + 1,8x10⁻⁵x = 0
Solving for x:
x = - 0,0015 (Wrong answer, there is no negative concentrations)
x = 0,0015
As [H⁺] = x = 0,0015 and pH is -log [H⁺], pH of the solution is 2,82
2. The equivalence point is reached when moles of HC₂H₃O₂ are equal to moles of NaOH. Moles of HC₂H₃O₂ are:
0,0466L × (0,078mol / L) = 3,63x10⁻³ moles of HC₂H₃O₂
In a 1,135M NaOH, these moles are reached with the addition of:
3,63x10⁻³ moles × (L / 1,135mol) = 3,20x10⁻³L = 3,20mL of 1,135M NaOH
3. The initial moles of HC₂H₃O₂ are:
0,0172L × (0,128mol / L) = 2,20x10⁻³ moles of HC₂H₃O₂
As the addition of NaOH spent HC₂H₃O₂ producing C₂H₃O₂⁻. Moles of C₂H₃O₂⁻ are equal to moles of NaOH and moles of HC₂H₃O₂ are initial moles - moles of NaOH. That means:
0,46x10⁻³L NaOH × (0,155mol / L) = 7,13x10⁻⁵ moles of NaOH ≡ moles of C₂H₃O₂⁻
Final moles of HC₂H₃O₂ are:
2,20x10⁻³ - 7,13x10⁻⁵ = 2,2187x10⁻³ moles of HC₂H₃O₂
Using Henderson-Hasselbalch formula:
pH = pka + log₁₀ [C₂H₃O₂⁻] / [HC₂H₃O₂]
Where pka is -log ka = 4,74. Replacing:
pH = 4,74 + log₁₀ [7,13x10⁻⁵] / [2,2187x10⁻³ ]
pH = 3,25
I hope it helps!
Answer:
How many bonding electrons are present in this compound?
How many lone pair (non-bonding) electrons are present in this compound?
Answer:
Valence electrons in XeCl2 = 8 + 7 + 7 = 22.
Bonding electrons = 4.
Nonbonding electrons = 18.
Explanation:
Hello.
In this case, you can see the Lewis structure on the attached picture, in which you can see that there are since xenon has 8 valance electrons and each chlorine has 7 valence electrons, the total amount of valence electrons is:
Valence electrons in XeCl2 = 8 + 7 + 7 = 22.
Moreover, since each chlorine atom is bonding with one of the eight electrons of xenon (Lewis structure), we can see there are 4 bonding electrons.
Finally, since there are six nonbonding electrons per chlorine atom and six nonbonding electrons in xenon, the overall nonbonding electrons are:
Nonbonding electrons in XeCl2 = 6 + 6 + 6 = 18.
Regards.