life-is-full-of-questions

Oh, I think I get it. So Number of moles of substance is 0.025 mol Molar mass of substance is 331 g mol-1 Mass of a substance = (number of moles of substance) x (molar mass of substance) Mass of substance = 0.025 mol x 331 g mol-1 =8.275 g, as the mols cancel out. I hope this is it now.

0.025 mol l-1 is 0.025 mol/litre, so 0.025 mol in 1 litre. But if I multiplied : Mass of a substance = 0.025 mol l-1 x 331 g mol-1 It would not give the correct answer, as the mol/l s do not cancel each other, like they would in a division, and it would not result in grams. Or am I so tired, that I cannot think clearly anymore? Sorry.

Hello everyone! I am new to chemistry and am working on a question that I got stuck on. If anyone could help me to continue my work, it would be greatly appreciated. The chemist used a solution of lead nitrate, Pb(NO3)2, with a concentration of 0.025 mol l-1. If they were preparing one litre of this solution, what mass of lead nitrate should they weigh out? For the initial calculations, I used the relative atomic mass (RAM) for each element and got the result for : RMM Pb(NO3)2 = 331 The relative molecular mass of lead nitrate is 331. The mass of one molecule of lead nitrate is 331 g. The molar mass of lead nitrate is 331 g mol-1. I was supposed to use this equation (as that is the only one we were shown, but I am not sure how: Mass of a substance = (number of moles of substance) x (molar mass of substance) The concentration mol l-1 is throwing me off too, as surely the mass needs to be in grams in the end. Can anyone advise me on this matter? Thank you in advance