. Which of the following is a chemical reaction? A. breaking a glass pane B. freezing water C. digestion of food D. cutting down a tree E. evaporation of rubbing alcohol

C. digestion of food

Explanation:

in a chemical reaction the substance changes composition and the reaction is mostly irreversible.

option C: digestion of food is a chemical reaction which changes the composition of the food we eat. Enzymes and other substances react with the food and turn it into soluble substances which the body can easily use.

option A: breaking glass does not change the composition of the glass plane. Its a physical reaction

option B: freezing water changes the state of water but the composition is still     the same, its a physical reaction as well.

option D: cutting a tree does not change the composition of the wood. This, too, is a physical reaction.

option E: when a liquid evaporates it changes into a gas, which is a change in the state of matter (just like water into ice), this also does not change the composition of alcohol.

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

earthquakes in florida are rare because the state is not located near any tectonic plates. in fact, florida is tied for first place as having the fewest earthquakes of any state. much of florida is limestone and seafloor materials that is not conducive to earthquakes.

explanation: