2021년 3월 모의_[ 고1 ]_37번
❶ If you had to write a math equation, you probably wouldn’t write, “Twenty-eight plus fourteen equals forty-two.”
❷ It would take too long to write and it would be hard to read quickly.
You would write, “28+14=42.”
❸ Chemistry is the same way.
❹ Chemists have to write chemical equations all the time, and it would take too long to write and read if they had to spell everything out.
❺ So chemists use symbols, just like we do in math.
❻ A chemical formula lists all the elements that form each molecule and uses a small number to the bottom right of an element’s symbol to stand for the number of atoms of that element.
❼ For example, the chemical formula for water is H2O.
❽ That tells us that a water molecule is made up of two hydrogen (“H” and “2”) atoms and one oxygen (“O”) atom.
