Answer:
Four covalent bonds.
Explanation:
Hello,
In this case, given the attached picture in which you can find the Lewis dot structure for metanal (formaldehyde) we can see two C-H bonds and two C-O bonds via a double bond, thus, we can compute the type of each bond given the electronegativities of hydrogen, carbon and oxygen which are 2.1, 2.5 and 3.5 respectively:

Thus, since both electronegativity difference are less 1.7 we infer that all of them are covalent, therefore, it has four covalent bonds, two C-H bonds and a double C-O bond.
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<u>Answer:</u>
2.0158 grams
<u>Explantion:</u>
We are to find the mass of the hydrogen atoms in 1 mole of water.
We know that the formula of water is: 
We can see, from the above mentioned formula, that water has 2 hydrpgen atoms.
From the periodic table, we get to know that Hydrogen has an atomic mass of 1.00794 grams.
As there are 2 atoms of hydrogen in water so
grams is the answer
Answer:
173.83 mmHg is the vapor pressure of a ethylene glycol solution.
Explanation:
Vapor pressure of water at 65 °C=
Vapor pressure of the solution at 65 °C= 
The relative lowering of vapor pressure of solution in which non volatile solute is dissolved is equal to mole fraction of solute in the solution.
Mass of ethylene glycol = 22.37 g
Mass of water in a solution = 82.21 g
Moles of water=
Moles of ethylene glycol=



173.83 mmHg is the vapor pressure of a ethylene glycol solution.