Given the following equation: 2C6H6 + 1502 - 12CO2 + 6H20 How many moles of O2 are needed to react with 4.0 moles of
Co HG?
a 30 moles
b 12 moles
C 4.0 moles
d 24 moles

a) 30 moles

Explanation:

                           2C6H6 + 1502 > 12CO2 + 6H20

from reaction      2 mol       15 mol

given                    4.0 mol     x mol

x = 4.0*15/2 = 30. mol

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

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

they are made of gases.

they have a spherical shape.

they make energy through fusion.