Select all that apply:

a)the mass ratio of oxygen to carbon in co is twice the mass ratio of oxygen to carbon in co2.
b)the mass ratio of oxygen to carbon in co is 1.33 for every sample of co.
c)mass ratio of oxygen to carbon in co2 is 2.667 for every sample of co2.
d)for two compounds of c and o, the mass ratio of c to o in one compound is a multiple of the mass ratio of c to o in the other compound.

Option B, C and D are correct.

Carbon is a non metallic element with the atomic number 6 and mass number 12. Whereas oxygen is also a non metallic element with the atomic number 8 and mass number of 16.

In carbon monoxide, the mass ratio of oxygen to carbon is 16:12 =1.33. This ratio is same for every sample of carbon monoxide, because carbon monoxide has the universal formula of CO.

Similarly In carbon dioxide , the mass ratio of oxygen to carbon is 32:12 =2.667. This ratio is same for every sample of carbon dioxide, because carbon dioxide has the universal formula of .

Even we can see that the mass ratio of oxygen to carbon in carbon dioxide is just twice the mass ratio of oxygen to carbon in carbon monoxide, because of presence of twice as much as oxygen per molecule of carbon dioxide than carbon monoxide.

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

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.