What is the chemical formula for butane

Omg imgonnafailnfiedkla use complete sentences to explain how the mass of hydrogen is conserved during cellular respiration.

Calculate the number of molecules present in 0.750 mol of mgo.

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3 -> a2cr(no3)3 + a3ag2so4