How many grams of a 34.2% potassium sulfate solution would contain 274.4 g potassium sulfate?

What is the chemical formula of the following compound

What are the resulting coefficients when you balance the chemical equation for the combustion of ethane, c2h6? in this reaction, ethane is burned in the presence of oxygen (o2) to form carbon dioxide (co2) and water (h2o). (g)+(g)→(g)+(g)

Why does his teacher ask him to balance the equation by including the correct coefficient