The formula of water molecule is`H_2O`. What information do you get from this formula?

What information do you get from the symbol of an element ?

What information do we get from the Mughal chronicle?

2Cu+O_2 to 2CuO what information do you get from this equation?

What information do you get from a balanced chemical equation?

Glucose reacts with bromine water to give gluconic acid. What information do you get from this reaction about the structure of glucose?