For the reaction C2H4(g) + 302(g) → 2002 (g) + 2H20 (8)
if 6.0 mol of CO2 are produced, how many moles of Oz were reacted?
4.0 mol
0 7.5 mol
9.0 mol
o none of these
O 15 mol

9.0 mol

Explanation:

In order to convert from moles of CO₂ to moles of O₂, we need to use the stoichiometric coefficients in the balanced reaction. We use a conversion factor that has moles of CO₂ in the denominator and moles of O₂ in the numerator:

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.