I think it is "Known".
Radioactive decay is measured using a formula where the half-life <span>of an isotope is the time it takes for the original nuclei to decay half of its original amount.</span>
Answer to this question is C. Regarding the volume.
The answer should be; 11
The atomic mass number is found by combining the number of protons and neutrons
Hope this helps :)
Enthalpy of formation is calculated by subtracting the total enthalpy of formation of the reactants from those of the products. This is called the HESS' LAW.
ΔHrxn = ΔH(products) - ΔH(reactants)
Since the enthalpies are not listed in this item, from reliable sources, the obtained enthalpies of formation are written below.
ΔH(C2H5OH) = -276 kJ/mol
ΔH(O2) = 0 (because O2 is a pure substance)
ΔH(CO2) = -393.5 kJ/mol
ΔH(H2O) = -285.5 kJ/mol
Using the equation above,
ΔHrxn = (2)(-393.5 kJ/mol) + (3)(-285.5 kJ/mol) - (-276 kJ/mol)
ΔHrxn = -1367.5 kJ/mol
<em>Answer: -1367.5 kJ/mol</em>
Mole fraction<span> is another way of expressing the concentration of a solution or mixture. It is equal to the </span>moles<span> of one component divided by the total </span><span>moles.
mass CH4O = 0.270 (51) = 13.77 g methanol
water = 51 - 13.77 = 37.23 g water
Hope this answers the question. Have a nice day.</span>
