Answer:
A wave pattern organizes a speech
Answer:
The number of moles of benzaldehyde = 0.0253 moles
Explanation:
The molecular formula of benzaldehyde is C₇H₆O
Its molecular mass is calculated from the atomic masses of the constituent atoms.
C = 12.0 g: H = 1.0 g; O = 16.0 g
Molecular mass = ( 12 * 7) + (1 * 6) + (16 * 1) = 106.0 g/mol
Number of moles of substance = mass of substance/ molar mass of the substance
mass of benzaldehyde = 2.68; molar mass = 106.0 g/mol
Number of moles of benzaldehyde = 2.68 g/ 106 g/mol = 0.0253 moles
Therefore, the number of moles of benzaldehyde = 0.0253 moles
Your question isn't quite clear, but if you're wondering if a chemical is polar or non-polar, you simply draw a VSEPR sketch and draw arrows where the bonds are. Only draw arrows between atoms, NOT between an atom and a lone pair of electrons. The arrow should point to the most electronegative atom (you should be given an electronegativity scale). Afterwards, you add up the arrows as vectors, and look at the sum of the vectors. If the sum is zero (CH4 is a good example), the chemical is non-polar. If the sum is a vector, the chemical is polar (H2O, or water, is polar).
Answer:
A) t = 22.5 min and B) t = 29.94 min
Explanation:
Initial concentration, [A]₀ = 100
Final concentration = 100 -75 = 25
Time = 45 min
A) First order reaction
ln[A] − ln[A]₀ = −kt
Solving for k;
ln[25] − ln[100] = - 45k
-1.386 = -45k
k = 0.0308 min-1
How long after its start will the reaction be 50% complete?
Initial concentration, [A]₀ = 100
Final concentration, [A] = 100 -50 = 50
Time = ?
ln[A] − ln[A]₀ = −kt
Solving for k;
ln[50] − ln[100] = - 0.0308 * t
-0.693 = -0.0308 * t
t = 22.5 min
B) Zero Order
[A] = [A]₀ − kt
Using the values from the initial reaction and solving for k, we have;
25 = 100 - k(45)
-75 = -45k
k = 1.67 M min-1
How long after its start will the reaction be 50% complete?
Initial concentration, [A]₀ = 100
Final concentration, [A] = 100 -50 = 50
Time = ?
[A] = [A]₀ − kt
50 = 100 - (1.67)t
-50 = - 1.67t
t = 29.94 min
Answer:
0.098 moles
Explanation:
Let y represent the number of moles present
1 mole of Ba(OH)₂ contains 2 moles of OH- ions.
Hence, 0.049 moles of Ba(OH)2 contains y moles of OH- ions.
To get the y moles, we then do cross multiplication
1 mole * y mole = 2 moles * 0.049 mole
y mole = 2 * 0.049 / 1
y mole = 0.098 moles of OH- ions.
1 mole of OH- can neutralize 1 mole of H+
Therefore, 0.098 moles of HNO₃ are present.
