Answer:
Explanation:
In CF4 and NF3, the valence electron groups on the central C and N atoms have a tetrahedral arrangement. The shapes of the molecules are determined by the number of bonding and nonbonding of electrons: since CF4 has four bonded atom(s) and zero lone pair(s) of electrons, the shape is tetrahedral.
Density is a property of a material which describes the mass of a material per unit volume. Density is said to be slightly dependent on temperature. We look at the density of water at different temperatures:
<span>
100 </span>°C: 958.4 kg/m^360 °C: 983.2 kg/m^320 <span>°C</span>: 998.2 kg/m^3
Therefore, warm water has a lower density than water in colder temperature.
To calculate the number of atoms of Cr, we first find the number of moles per unit of cubic centimeter of Cr. Then, use avogadros number for the number of atoms. Calculations are as follows:
1 cm^3 (7.15 g/cm^3) (1 mol / 51.996 g Cr) = 0.14 mol Cr
0.14 mol Cr ( 6.022 x 10^23 atoms Cr / 1 mol Cr ) = 8.28 x 10^22 atoms Cr
