The mass of a sample weighed on an electronic balance that is sensitive to 0.3 mg is 1.2300 g. the number of significant figures in this measurement is

The sensitivity of electronic balance is 0.3 mg

Converting 0.3 mg to g:

g

So, the mass of a substance weighed on the balance can be measured accurately up to four decimal places.

Given the mass of sample is 1.2300 g. The number of significant figures in the measurement will be 5 because the balance can measure the mass of a sample accurately up to four decimal points, all the digits in the measurement will be significant.

chemists can use the electron cloud model to assign electrons to different atomic orbitals. atomic orbitals also explain the patterns in the periodic table

explanation:

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.