The problem states, 'A student wants to determine how long it takes to dissolve 51.3 g of common table salt (sodium chloride) in 1L of water by monitoring the solution. It takes 26.7 seconds for the salt to completely dissolve. Determine the rate of dissolution and describe the rate constant expression if the reaction was first-order in NaCl.'

Question

For the first bit, I multiplied the mass by the molar mass of NaCl to get about 0.878 moles and then divided that by the time to get about 0.0329 mol/s. Does that sound about right?

For the second bit, do they just want me to say rate=k[NaCl]?

Thanks!

Answer 1

A couple of points here. First, mol = grams/molar mass and not what you have. Then mols/L/s will give you about 0.0344 M/s and not mols/s.