How many grams of pure, solid naoh are required to make 400 ml of 0.1m naoh solution? express your answer to 2 significant figures, e. g. 3.3 g?

In this question, you want to make 400 ml of 0.1m NaOH solution. The amount of NaOH in mol should be:

molar= mole of NaOH/l of water
0.1m= mol of NaOH/ 0.4l
mol of NaOH= 0.1* 0.4= 0.04 mol

The molecular weight for NaOH should be 40g/mol. Then the amount of NaOH in grams would be: 0.04 * 40(g/mol) = 1.6 grams

Gallium melts near room temperature and has one of the largest  liquid  ranges of any metal, so it has found use in high temperature thermometers.