Answer:
True; When one side of a molecule is electronegative (δ-) and the other side of the
molecule is electropositive (δ+), it is said to have a dipole moment.
Explanation:
A dipole moment exists in a molecule as a result of differences in the electronegativity values between the atoms of the elements involved in the chemical bonding.
When a strogly electronegative atom such as oxygen or chlorine is chemically bonded to a less electronegative or an electropositive atom such as hydrogen, there is an uneven sharing of the electrons involved in the bonding. The more electronegative atoms tends to draw the shared electrons mostly to themselves. This induces a partially negative charge (δ-) on them while leaving the electropositive atoms with a partially positive charge (δ+).
Water is an example of a molecule having a dipole moment. The oxygen atoms are more electronegative than hydrogen and as such draw the shared electrons to themselves more, inducing a partial positive charge (δ+) on the hydrogen atoms while they themselves develop a partial negative charge (δ-).
Answer: C. ethanol
The enthalpy of combustion is the amount of heat produced when one mole of ethanol undergoes complete combustion at 25 ° C and 1 atmosphere pressure, yielding products also at 25 ° C and 1 atm.
<u>The enthalpy of combustion of the unknown compound is</u>
ΔH = - 320 kJ / 0.25 mol = - 1280 kJ / mol
<u>To choose a probable compound according to this combustion enthalpy, we must evaluate the deviation in relation to the values reported in the literature for the three probable compounds</u> (methane, ethylene and ethanol). The deviation (e%) will be calculated according to the following equation,
e% = ( | ΔHx - ΔH | / ΔHx ) x 100%
where ΔHx is the enthalpy of combustion of the probable compound.
The following table shows the combustion enthalpies of the probable compounds and their deviation in relation to the enthalpy of ΔH = - 1280 kJ / mol
Compound Enthalpy of combustion (kJ/mol) Deviation
Methane - 890.7 43.8%
Ehylene -1411.2 9.3%
Ethanol -1368.6 6.5%
According to the previous table, we can say that the most probable compound is ethanol, since it has the smallest deviation in relation to the experimental enthalpy value of combustion.
N(C)=5,02·10²² atoms
calculation check:
N(C)=(1/12)*6.022*10²³=0.5018*10²³≈5.02·10²²
Answer:
Using the formula cards again, add the coefficient of 2 in front of the formula and have them recalculate the number of each element and the total number of atoms in each element.
Explanation:
