Answer:
[H⁺] = 1.58 x 10⁻⁷ M.
Explanation:
∵ pOH = - log[OH⁻]
7.20 = - log[OH⁻]
log[OH⁻] = - 7.20
∴ [OH⁻] = 6.31 x 10⁻⁸.
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(6.31 x 10⁻⁸) = 1.585 x 10⁻⁷ M.
Vanillin is the common name for 4-hydroxy-3-methoxy-benzaldehyde.
See attached figure for the structure.
Vanillin have 3 functional groups:
1) aldehyde group: R-HC=O, in which the carbon is double bonded to oxygen
2) phenolic hydroxide group: R-OH, were the hydroxyl group is bounded to a carbon from the benzene ring
3) ether group: R-O-R, were hydrogen is bounded through sigma bonds to carbons
Now for the hybridization we have:
The carbon atoms involved in the benzene ring and the red carbon atom (from the aldehyde group) have a <u>sp²</u> hybridization because they are involved in double bonds.
The carbon atom from the methoxy group (R-O-CH₃) and the blue oxygen's have a <u>sp³</u> hybridization because they are involved only in single bonds.
1) Find the number of molecules in 7.88 g of sulfur
molar mass of S8 = 8*atomic mass of S = 8 * 32.0 g / mol = 256.0 g/mol
Number of moles = mass in grams / atomic mass = 7.88 g / 256.0 g / mol = 0.0308 moles
2) Find the mass of 0.0308 moles of P4
mass = number of moles * molar mass
molar mass of P4 = 4 * atomic mass of P = 4 * 31 g/mol = 124 g/mol
mass of P4 = 0.0308 moles * 124 g/mol = 3.8192g ≈ 3.82 g.
Answer: 3.82 grams of P4 will have the same number of molecules as 7.88 g of S8 (that is 0.0308 moles of molecules)
0.216g of aluminium compound X react with an excess of water water to produce gas. this gas burn completely in O2 to form H2O and 108cm^3of CO2 only . the volume of CO2 was measured at room temperature and pressure
0.108 / n = 24 / 1
n = 0.0045 mole ( CO2 >>0.0045 mole
0.216 - 0.0045 = 0.2115
so Al = 0.2115 / 27 => 0.0078 mole
C = 0.0045 * 1000 => 4.5 and Al = 0.0078 * 1000 = 7.8