1 The question asks for a certain quantity of examples in a list (Name 6 factors that contributed to the start of World War I, What 3 subatomic particles constitute an atom? etc).
2 The question is academically precise and, therefore, indecisive in the wording (What are the 2 kinds of loading most professional engineers and academics in the field of engineering today generally consider to be relevant in most cases when considering typical types of structure usually made of common materials using well-understand methods?)
3 The question challenges the answerer to defend a position as opposed to merely rattling off a list based on knowledge alone, thereby invoking higher levels of Bloom's Taxonomy. (What are 4 arguments that could be used to defend arguments made by the physicists of the day that electromagnetic waves must move through an illusive substance called 'the ether?)
These are the characteristics that apply:
- In a solution taste sour: which is consequence of the H+ concentration.
- Corrode metals: the H+ ion reacts with the metal producing a salt and water
-Produce hydronium ion in solution: as per the Bronsted - Lowry definition an acid is a substance that donates a proton, H+. This proton will react with H2O to form H3O+ (hydronium), as per this scheme:
HA + H2O --> A(-) + H3O(+)
A baseball will curve better on the flat plain if it is higher than sea level but low elevation.
Hope this helped!