Which represents a balanced chemical equation?

What’s the percent by mass of carbon in c10h14n2

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?

If blood contains 150g of hemoglobin per liter of blood, how much hemoglobin would be contained in 10 ml of blood