The balance you used for weighing the metal strip does not zero properly, and consequently, all of your mass measurements are high by precisely 0.050 g (e. g., if you read "20.450 g", the real value was 20.400 g). What effect would this have on your experimental value of Avogadro's Number?

d.) the average kinetic energy of the gas particles is greater in container b because its particles move faster.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).