Which of the following is a correct description of a double bond between two carbon atoms?

a double bond will produce four single bonds to form a tetrahedral shape.
a double bond between carbon atoms will eventually form a ring of carbons.
a double bond between carbon atoms is longer than a triple bond between carbon atoms.
a double bond will quickly reduce to single bonds to create three-dimensional tetrahedra.

its first and third is your answer i did the qustion the fourth isnt right

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.