The tilt of the earth provides the earth with seasons. As the earth revolved around the sun different portions (northern or Southern Hemisphere) is exposed more directly to the suns radiation, thus it is hotter in those regions. (Why the United States experiences winter in December but Australia experience summer in December.)
Answer:
2/3
Explanation:
Crystals structures can also be seen when two elements combines together and the perfect example is Al₂O₃ which is given in the question above. Just like it is given in the question above, the kind of arrangement in the crystal structure for Al₂O₃ is called HCP which stands for Hexagonally Closed Pack.
The aluminum ions which is in form of Al³⁺ occupies the two-third[2/3] positions while the position that the oxygen ion occupies is one[1].
Frequency is defined as the number of waves per second. In this machine 25 waves pass in one second.
We need to calculate the number of waves that pass a particular point during one second.
During 2 seconds -25 waves
Therefore in one second - 25/2 = 12.5 waves/s.
1 wave per second has the unit Hertz (Hz)
Therefore answer is 12.5 Hz
They are described through the use of four physical properties or macroscopic characteristics: pressure, volume, number of particles (chemists group them by moles) and temperature.
Answer:
dipole-dipole forces, ion-dipole forces, higher molar mass, hydrogen bonding, stronger intermolecular forces
Explanation:
<em>1. H₂S and H₂Se exhibit the following intermolecular forces: </em><em>dipole-dipole forces </em><em>and </em><em>ion-dipole forces</em><em>.</em> These molecules have a bent geometry, thus, a dipolar moment which makes them dipoles. When they are in the aqueous form they are weak electrolytes whose ions interact with the water dipoles
<em>2. Therefore, when comparing H₂S and H₂Se the one with a </em><em>higher molar mass</em><em> has a higher boiling point.</em> In this case, H₂Se has a higher boiling point than H₂S due to its higher molar mass.
<em>3. The strongest intermolecular force exhibited by H₂O is </em><em>hydrogen bonding</em><em>. </em>This is a specially strong dipole-dipole interaction in which the positive density charge on the hydrogens is attracted to the negative density charge on the oxygen.
<em>4. Therefore, when comparing H₂Se and H₂O the one with </em><em>stronger intermolecular forces</em><em> has a higher boiling point. </em>That's why the boiling point of H₂O is much higher than the boiling point of H₂Se.
