Which person below is moving the fastest? D A B distance time

In what situations are van der waals forces the most significant

viktelen [127]

Its most significant when all other forces are absent

7 0

3 years ago

An aqueous solution containing 17.5 g of an unknown molecular (nonelectrolyte) compound in 100.0 g of water has a freezing point

Sonbull [250]

Answer:

molar mass = 180.833 g/mol

Explanation:

mass sln = mass solute + mass solvent

∴ solute: unknown molecular (nonelectrolyte)

∴ solvent: water

∴ mass solute = 17.5 g

∴ mass solvent = 100.0 g = 0.1 Kg

⇒ mass sln = 117.5 g

freezing point:

ΔTc = - Kc×m

∴ ΔTc = -1.8 °C

∴ Kc H2O = 1.86 °C.Kg/mol

∴ m: molality (mol solute/Kg solvent)

⇒ m = ( - 1.8 °C)/( - 1.86 °C.Kg/mol)

⇒ m = 0.9677 mol solute/Kg solvent

molar mass (Mw) [=] g/mol

∴ mol solute = ( m )×(Kg solvent)

⇒ mol solute = ( 0.9677 mol/Kg) × ( 0.100 Kg H2O )

⇒ mol solute = 0.09677 mol

⇒ Mw solute = ( 17.5 g ) / ( 0.09677 mol )

⇒ Mw solute = 180.833 g/mol

6 0

3 years ago

True or false. Air masses mix at fronts?

Elina [12.6K]

The correct answer is False

6 0

3 years ago

Name two compounds with more exothermic lattice energies than scandium oxide and justify your choice.

N76 [4]

Answer:

1 . $Al_2O_3$

2. $TiO_2$

Explanation:

The more stable the ionic compound, the more is it lattice energy.

The more the charge on the cation and the anion, the greater is the lattice energy.
The less the size of the cation and the anion, the greater is the lattice energy.

Scandium oxide ( $Sc_2O_3$ ) is an oxide in which $Sc^{3+}$ behaves as cation and $O^{2-}$ behaves as anion.

The compounds which has higher lattice energy than scandium oxide are:

1 . $Al_2O_3$

This is because the charge are same on the cation and the anion as in the case of the Scandium oxide but the size of the cation $Al^{3+}$ is smaller than $Sc^{3+}$ . Thus, this corresponds to higher lattice energy.

2. $TiO_2$

This is because the charge on the cation $Ti^{4+}$ is greater than that of $Sc^{3+}$ and also the size of the cation $Ti^{4+}$ is smaller than $Sc^{3+}$ . Thus, this corresponds to higher lattice energy.

3 0

3 years ago

Hydrogen peroxide can decompose to water and oxygen by the following reaction

mestny [16]

To begin calculating, there is one thing you need to remember : $1 mole of H2O2=34.0148 g$
Then we have $5.00g of H2O2=5/34.0148=0.146995$
As you know decomposition of 2moles now has prodused 196kj
So, q is made due $0.146995 moles of H2O2$ $=(-196/2)*0.146995=-14.40551Kj$
I'm sure it will help.

6 0

3 years ago