Answer:
grams
Explanation:
Complete question is
You are asked to pre pare a pH = 4.00 buffer starting from 1.50 L of 0.0200 M solution of benzoic acid
(C6H5COOH)
and any amount you need of sodium benzoate
(C6H5COONa)
How many grams of sodium benzoate should be added to prepare the buffer? Neglect the small volume change that occurs when the sodium benzoate is added.
Solution
Given
pH of the buffer solution 
Concentration of C6H5COOH
M
Volume of the buffer solution
L
value for benzoic acid is 
Concentration of sodium benzoate

Substituting the given values we get

Number of moles in sodium benzoate

Mass of sodium benzoate

- For solving this problem, we have to take in account the degree of freedom of air molecules.
- As, molecules of air have five degrees of freedom (three translational and two rotational)
- For each molecule, the kinetic energy of each degree of freedom = 1/2 KT
- So, K.E of 1 molecule for 5 degrees of freedom = 5/2KT
So, for molecules of air K.E = 5/2 KT = 5/2 x 1 x 1.38 x 10⁻²³ x 308 = 1062.6 x 10⁻²³ J
1 mole of air contains 6.022 x 10²³ molecules
K.E. of 1 mole = 1062.6 x 10⁻²³ x 6.022 x 10²³ = 6400 J
12.3g 02times1 mol 02/32.0 g 02=mol 02
.38mol/x=20.95/100
x=1.8mol air...
PV=nRT
101.3kPa times V =1.8 mol times 8.31[kPa *L]/{k*mol}*273k
V=40.3Lair
66 mph
Explanation:
Average speed is the rate of change of distance with time:
Average speed = 
Given parameters:
Starting point = 88mile marker
End of journey = 121mile marker
time = 30minutes = 0.5hr(60min = 1hr)
Solution:
The distance covered in this journey:
Distance = End of journey - starting point = 121 mile - 88 mile = 33mile
Average speed = 
= 66mph
The average speed of Sara's mum is 66mph
Learn more:
Average speed brainly.com/question/8893949
#learnwithBrainly
Most likely use scientific names and list the procedures taken