0.022
(Correct to two significant figures)
The nucleus is made of protons and neutrons. It has a positive charge.
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.
Answer:
52.99 kPa
Explanation:
Initial volume V1 = 2.7 L
Initial Pressure P1 = 78.5 kPa
Final Volume V2 = 4.0L
Final Pressure P2 = ?
Temperature is constant
The relationship between these quantities is given by the mathematical expression of Boyles law. This is given as;
V1P1 = V2P2
P2 = V1P1 / V2
P2 = 2.7 * 78.5 / 4.0
P2 = 52.99 kPa
Electrons determine the chemical properties. Protons and neutrons are in the nucleus the number of protons determines the number of electrons of an atom
