Why do need thermometer , thermistors and other devices for measuring temperature

The density of an unknown gas at 98°c and 740 mmhg is 2.50 g/l. what is the molar mass of the gas with work showed?

Idon't really understand this can you me and show your work.☺☺[ chemistry b] subject [ electron transfer in lonic bonds]grade( 12)

Achemist 16 drop copper metal from copper chloride solution. the chemist place is 0.50 g of aluminum foil in a solution containing 0.75 g of copper (ii) chloride. a single replacement reaction takes place. which statement explains the maximum amount of copper that the chemist can extract using this reaction?