4 Some elements have symbols that do not appear to match their names. For example, the symbol for sodium is Na. Why is this?

Find the missing probability in the table below a.0.10 b.40 c.0.80 d. 0.20

15) a substance used in manufacturing gasoline consists of finely divided platinum supported on an inert solid. suppose that the platinum is formed by the high temperature reaction between platinum (iv) oxide and hydrogen gas. the other product is water. a) write and balance the equation b) how many grams of hydrogen are needed to produce 1.0 g of platinum metal? c) how many moles of water are produced at the same time? how many grams? ( show work, .)

Question 2 (5 points) which of the following materials is useful for making molds because it has a low melting point? question 2 options: wood metal wax sand