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2 years ago

12. Compare and contrast hydrogen bonds and van der Waals interactions.

Chemistry

1 answer:

mrs_skeptik [129]2 years ago

4 0

Explanation:

Van der Waals interactions occur between any two or more molecules. They are caused by a fluctuation in electron density, as electrons are not actually fixed in a shell, but actually freely moving as a 'cloud of electron density'. This means that sometimes one end of a molecule can become more partially negatively charged as all electrons move to that side, and conversely it can attract the more partially positive end of a molecule (that has little electrons).

Hydrogen bonds only occur between molecules that contain oxygen, nitrogen and fluorine bonded to a hydrogen atom.

Hydrogen bonding is also the strongest intermolecular force there is, but not strong in comparison to ionic and covalent bonds. Therefore, hydrogen bonds are much stronger than Van der Waals forces. Hydrogen bonds only form if oxygen, nitrogen and fluorine are bonded to a hydrogen atom, as they have the greatest electronegativity differences (look at an electronegativity table), and when the overall molecule is polar (have unequal charges). This allows the molecule to be able to attract another molecule from one of the bonded atoms to a hydrogen atom.

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A sample of 1.000 g of a compound containing carbon and hydrogen reacts with oxygen at elevated temperature to yield 0.692 g H₂O

ollegr [7]

Answer :

(a) 1.000 g of compound containing carbon and hydrogen is, 0.922 g and 0.0769 g respectively.

(b) There is no other element present in the compound.

Explanation :

(a) Now we have to determine the masses of C and H in the sample.

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_y+O_2\rightarrow CO_2+H_2O$

where, 'x' and 'y' are the subscripts of Carbon and hydrogen respectively.

We are given:

Mass of $CO_2=3.381g$

Mass of $H_2O=0.692g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 3.381 g of carbon dioxide, $\frac{12}{44}\times 3.381=0.922g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18 g of water, 2 g of hydrogen is contained.

So, in 0.692 g of water, $\frac{2}{18}\times 0.692=0.0769g$ of hydrogen will be contained.

Thus, 1.000 g of compound containing carbon and hydrogen is, 0.922 g and 0.0769 g respectively.

(b) Now we have to determine the compound contain any other elements or not.

Mass carbon + Mass of hydrogen = 0.922 g + 0.0769 g = 0.999 g ≈ 1 g

This means that there is no other element present in the compound.

3 0

3 years ago

The molar mass of I2 is 253.80 g/mol, and the molar mass of NI3 is 394.71 g/mol. How many moles of I2 will form 3.58 g of NI3?

Nat2105 [25]

To answer the problem above first we need to find the difference of molar mass of NI3 from I2, 394.71 g/mol - 253.80 g/mol = 140.91 g/mol. Knowing the molar mass of the difference of NI3 from I2, in equation mass (g) / moles (mol) = molar mass, then we substitute. 3.58g / moles = 140.91 g/mol.
moles = 3.58 / 140.91 = 0.025 moles.

6 0

3 years ago

PROMISE I WILL MARK BRAINIEST NOT MUCH TIME

Galina-37 [17]

Your answer would be c

hope this helps

4 0

3 years ago

A 25.0-mL sample of 0.150 M butanoic acid is titrated with a 0.150 M NaOH solution. What is the pH before any base is added? The

hoa [83]

HA ⇄ H⁺ + A⁻
so:
$\frac{[H^+][A^-]}{[HA]} = 1.5 x 10^{-5}$
and now:
$\frac{(x)(x)}{(0.150-x)}$ = 1.5 x 10⁻⁵
x is considered very small compared to 0.15
x² = 2.25 x 10⁻⁶
x = 1.5 x 10⁻³
So [H⁺] = 1.5 x 10⁻³
pH = - log [H⁺] = - log (1.5 x 10⁻³) = 2.83

7 0

3 years ago

What propertys does the rock state-of -matter have that wont let Logan poke his finger through it?

adell [148]

A rock is a solid, so Logan can't poke his finger through it.

4 0

3 years ago