Hydrogen bonds are not like covalent bonds. They are nowhere near as strong and you can't think of them in terms of a definite number like a valence. Polar molecules interact with each other and hydrogen bonds are an example of this where the interaction is especially strong. In your example you could represent it like this:
<span>H2C=O---------H-OH </span>
<span>But you should remember that the H2O molecule will be exchanging constantly with others in the solvation shell of the formaldehyde molecule and these in turn will be exchanging with other H2O molecules in the bulk solution. </span>
<span>Formaldehyde in aqueous solution is in equilibrium with its hydrate. </span>
<span>H2C=O + H2O <-----------------> H2C(OH)2</span>
Question:
Zinc metal is added to hydrochloric acid to generate hydrogen gas and is collected over a liquid whose vapor pressure is the same as pure water at 20.0 degrees C (18 torr). The volume of the mixture is 1.7 L and its total pressure is 0.987 atm. Determine the number of moles of hydrogen gas present in the sample.
A. 0.272 mol
B. 0.04 mol
C. 0.997 mol
D. 0.139 mol
E. 0.0681 mol
Answer:
The correct option is;
E. 0.0681 mol
Explanation:
The equation for the reaction is
Zn + HCl = H₂ + ZnCl₂
Vapor pressure of the liquid = 18 torr = 2399.803 Pa
Total pressure of gas mixture H₂ + liquid vapor = 0.987 atm
= 100007.775 Pa
Therefore, by Avogadro's law, pressure of the hydrogen gas is given by the following equation
Pressure of H₂ = 100007.775 Pa - 2399.803 Pa = 97607.972 Pa
Volume of H₂ = 1.7 L = 0.0017 m³
Temperature = 20 °C = 293.15 K
Therefore,

Therefore, the number of moles of hydrogen gas present in the sample is n ≈ 0.0681 moles.
Answer:
The partial pressure of NO2 = 0.152 atm
Explanation:
Step 1: Data given
Pressure NO2 = 0.500 atm
Total pressure at equilibrium = 0.674 atm
Step 2: The balanced equation
2NO2(g) → 2NO(g) + O2(g)
Step 3: The initial pressure
pNO2 = 0.500 atm
pNO = 0 atm
p O2 = 0 atm
Step 4: Calculate pressure at the equilibrium
For 2 moles NO2 we'll have 2 moles NO and 1 mol O2
pNO2 = 0.500 - 2x atm
pNO =2x atm
pO2 = xatm
The total pressure = p(total) = p(NO2) + p(NO) + p(O2)
p(total) = (0.500 - 2x) + 2x + x= 0.674 atm
0.500 + x = 0.674 atm
x = 0.174 atm
This means the partial pressure of NO2 = 0.500 - 2*0.174 = 0.152 atm
Add the Pressure of neon and argon that is 0.68 +0.35= 1.03
Total pressure that is 1.25 -1.03=0.22 atm