Calculate the minimum mass of sulfuric acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.

Full Question:

Aqueous sulfuric acid H2SO4 will react with solid sodium hydroxide NaOH to produce aqueous sodium sulfate Na2SO4 and liquid water H2O. Suppose 94g of sulfuric acid is mixed with 49.9g of sodium hydroxide. Calculate the minimum mass of sulfuric acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.

Answer:

32.8725g

Explanation:

First thing's first, we write out the balanced chemical equation;

2NaOH + H2SO4 - -> Na2SO4 + 2H2O

The question hints that sulphuric acid would be in exess by asking to calculate the minium mass that would be left over.

We proceed by calculatng the amount of sulphuric acid that would react with 49.9g of sodium hydroxide.

From the reaction,

2 moles of NaOH reacts with 1 mole of H2SO4.

Calculate moles of sodium hydroxide:

Molar mass of NaOH = 40.0 g/mol

Mass of NaOH = 53 g

moles = Maass / Molar mass = 1.2475

This means 1.2475 would react with x number of moles;

2 = 1

1.2475 = x

x = 1.2475 / 2 = 0.62375

Mass of Sulphuric acid reacted = moles * molar mass = 0.62375 * 98 = 61.1275g

Mimium mass of left over = 94 - 61.1275g = 32.8725g