Answer:
sodium hydroxide
Explanation:
When sodium is dropped in cold water, it reacts explosively and burns with a golden yellow flame. The reaction is exothermic and vigourus. It form sodium hydroxide with the liberation of hydrogen gas.
You can calculate the mass of water by using the molar units to convert 7.63g of butane to moles and then find the molar mass of H2O which I think should be 1.01 + 1.01 + 16.00 if I remember correctly. That is 18.02moles/g. The butane is the limiting reactant but you would need the chemical equation to solve this
V is used to indicate Ecell ( just look at what measurement is simplified to V) <span />