Consider the balanced equation below.

2h2s + 3o2 > 2so2 + 2h2o

which option gives the correct mole ratios?
h2s: so2 = 2: 2 and o2: h2o = 3: 2
h2s: so2 = 2: 3 and o2: h2o = 3: 2
h2s: so2 = 4: 4 and o2: h2o = 5: 4
h2s: so2 = 4: 6 and o2: h2o = 4: 4

the balanced equation is as follows

2H₂S + 3O₂ --> 2SO₂ + 2H₂O

molar ratio also known as stoichiometry is the ratio in which the reactants and products are either formed or reacted in the given equation

molar ratio can be determined by the coefficients of the compounds in the balanced reaction

coefficient is the number in front of the chemical compound

coefficients for the compounds in this reaction are as follows

H₂S - 2

O₂ - 3

SO₂ - 2

H₂O - 2

therefore correct option is

H₂S:SO₂ = 2:2 and O₂:H₂O = 3:2

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.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.