What is the relative mass of an electron? a) 1/1840 the mass of a neutron + proton b) 1/1840 the mass of an alpha particle c) 1/1840 the mass of a c-12 atom d) 1/1840 the mass of a hydrogen atom

1/1840 the mass of a C-12 atom

Choice C is correct

Explanation:

The relative mass of an electron is 1/1840 the mass of a C-12 atom . Atomic mass units are expressed relatively to the atomic mass unit of an unbound neutral carbon-12 atom.

d) 1/1840 of hydrogen atom mass is the relative electron mass.

The hydrogen gas is the lightest element and its atomic mass is , same as the mass of proton because it has no neutron and contains one proton and one electron in its atom. But it loses an electron to gain stable electronic configuration leaving only a proton in its atomic structure.

We know, Mass of an electron =

Relative mass of electron = the mass of proton

Relative mass of electron = the mass of hydrogen atom.

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.