Answer:
0.084 M
Explanation:
Using the Henderson-Hasselbalch equation for a buffer ( a buffer is solution contain a weak acid and it conjugate base; the solution resist change in pH)
pH = pKa + log ( base/acid)
4.9 - 4.76 =log ( base / acid)
10^0.14 = ( base / acid)
1.38 = (base / acid)
since there is 0.2 M in the buffer solution
the concentration of acid = 
× 0.2 = 0.084 M
Its A Natural resources are found in abundance in the US.
Answer:
a thing that is composed of two or more separate elements ex. Acid and Water
Answer: (a) There are 0.428 moles present in 12 g of 
molecule.
(b) There are 2 moles present in 
particles of oxygen.
Explanation:
(a). The mass of nitrogen molecule is given as 12 g.
As the molar mass of is 28 g/mol so its number of moles are calculated as follows.
So, there are 0.428 moles present in 12 g of molecule.
(b). According to the mole concept, 1 mole of every substance contains 
atoms.
Therefore, moles present in particles are calculated as follows.
So, there are 2 moles present in particles of oxygen.
Answer: The energy (heat) required to convert 52.0 g of ice at –10.0°C to steam at 100°C is 157.8 kJ
Explanation:
Using this formular, q = [mCpΔT] and = [nΔHfusion]
The energy that is needed in the different physical changes is thus:
The heat needed to raise the ice temperature from -10.0°C to 0°C is given as as:
q = [mCpΔT]
q = 52.0 x 2.09 x 10
q = 1.09 kJ
While from 0°C to 100°C is calculated as:
q = [mCpΔT]
q = 52.0 x 4.18 x 100
q = 21.74 kJ
And for fusion at 0°C is called Heat of fusion and would be given as:
q = n ΔHfusion
q = 52.0 / 18.02 x 6.02
q = 17.38 kJ
And that required for vaporization at 100°C is called Heat of vaporization and it's given as:
q = n ΔHvaporization
q = 52.0 / 18.02 x 40.7
q = 117.45 kJ
Add up all the energy gives 157.8 kJ
