What elements from the periodic table are considered man-made?

Calculate the molarity of 48.0 ml of 6.00 m h2so4 diluted to 0.250 l .

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?

Which metal exist in liquid state and can be cut with knife ?