How many grams of sodium hydroxide is formed when 2.3 g of sodium reacts with water?

Given:
m (Na) = 2.3 g

To find:
m (NaOH) -?

Decision:
1) Write the reaction equation:
2Na + 2H2O => 2NaOH + H2;
2) Calculate the molar mass of Na:
M (Na) = Mr (Na) = Ar = 23 g / mol;
3) Calculate the amount of substance Na:
n (Na) = m (Na) / M (Na) = 2.3 / 23 = 0.1 mol;
4) Determine the amount of NaOH substance:
n (NaOH) = n (Na) = 0.1 mol;
5) Calculate the molar mass of NaOH:
M (NaOH) = Mr (NaOH) = Ar (Na) * N (Na) + Ar (O) * N (O) + Ar (H) * N (H) = 23 * 1 + 16 * 1 + 1 * 1 = 40 g / mol;
6) Calculate the mass of NaOH:
m (NaOH) = n (NaOH) * M (NaOH) = 0.1 * 40 = 4 g.

Answer: The mass of NaOH is 4 g.