Answer:
Average of measurements = 20.97 cm
Explanation:
Given data:
Three measurements of pete's = 20.9 cm, 21.0 cm, 21.0 cm.
Average value of measurements = ?
Formula:
Average of measurements = sum of all measurements / Total number of measurements
Solution:
Average of measurements = 20.9 cm + 21.0 cm + 21.0 cm. / 3
Average of measurements = 62.9 cm / 3
Average of measurements = 20.97 cm
Answer:
Hydrogen
Explanation:
It is considered a special element due to its flexibility in giving up & taking in electrons, therefore making it good for organic & inorganic chemistry. Hydrogen has only one proton and one electron and is the only element which has no neutrons. it is considered as the simplest element in the universe and gives a valid reason for it to be the most abundant and common element in the universe.
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Answer:
a. 0.182
b. 1.009
c. 1.819
Explanation:
Henderson-Hasselbach equation is:
pH = pKa + log [salt / acid]
Let's replace the formula by the given values.
a. 3 = 3.74 + log [salt / acid]
3 - 3.74 = log [salt / acid]
-0.74 = log [salt / acid]
10⁻⁰'⁷⁴ = 0.182
b. 3.744 = 3.74 + log [salt / acid]
3.744 - 3.74 = log [salt / acid]
0.004 = log [salt / acid]
10⁰'⁰⁰⁴ = 1.009
c. 4 = 3.74 + log [salt / acid]
4 - 3.74 = log [salt / acid]
0.26 = log [salt / acid]
10⁰'²⁶ = 1.819
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
