Delta H = q / mass * delta temperature
Answer:
a)calculated molarity of NaOH would be lower
b) calculated molarity of NaOH would be lower
c) calculated molarity of NaOH would be lower
d) calculated molarity of NaOH would be unaffected
Explanation:
Let us recall that the reaction of NaOH and HCl is as follows;
NaOH(aq) + HCl(aq) ----> NaCl(aq) + H2O(l)
Since the reaction is 1:1, when the number of moles of HCl reacting with NaOH is low due to dilution, the calculated molarity of NaOH also becomes less than it's accurate value.
When 40mL of water is added to the titration flask rather than 25ml of water, the acid is more dilute hence less number of moles of acid than necessary reacts with the base thereby yielding a less than accurate value of the molarity of NaOH.
If the burette wet with water is not rinsed with NaOH solution, the concentration of the NaOH in the burette decreases due to dilution with water and a less than accuracy value is calculated for the molarity of NaOH.
If five drops of phenolphthalein is used instead of one or two drops, there is no qualms since enough phenolphthalein may be added to ensure that a sharp end point is obtained.
Answer:
Mass = 4.6 g
Explanation:
Given data:
Number of molecules of sucrose = 8.1 ×10²¹ molecules
Mass of sucrose = ?
Solution:
First of all we will calculate the number of moles by using Avogadro number.
1 mole × 8.1 ×10²¹ molecules / 6.022×10²³ molecules
1.35 × 10⁻² mol
Mass of sucrose:
Mass = number of moles × molar mass
Molar mass = 342.3 g/mol
Mass = 1.35 × 10⁻² mol ×342.3 g/mol
Mass = 462.1 × 10⁻² g
Mass = 4.6 g
Answer:
2-chloro-4-methylpentanal.
Explanation:
Hello there!
In this case, according to the chemical compound:
CH3-CH-CH2-CH-CHO
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CH3 Cl
We can see the main functional group is an starting carbonyl, which means this is an aldehyde. Moreover, we can see a Cl-substituent on the second carbon and a methyl substituent on the fourth carbon. Therefore, the IUPAC name turns out: 2-chloro-4-methylpentanal.
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Answer: (3) The difference in electronegativity between carbon and oxygen is greater than that between fluorine and oxygen.
Explanation: Polarity of a molecule is due to the difference in electronegativity of the atoms. More is the electronegativity difference, more is the polarity.
Electronegativity of carbon = 2.5
Electronegativity of oxygen = 3.5
Electronegativity of fluorine = 4.0
Thus the difference in electronegativity of carbon and oxygen is=(3.5-2.5)= 1.0
Thus the difference in electronegativity of fluorine and oxygen is=(4.0-3.5)= 0.5.
Thus C-O bond is more polar than F-O bond.
