Ametal surface becomes dull because of continued abrasion physical change or chemical

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

At the current rate, a graph of carbon dioxide produced by fossil fuels over time would slope upward slope downward be horizontal be vertical

According to thomson, the atom is a positively charged cloud with electrons scattered throughout. what would the alpha particles do when they hit the foil if thomson were correct