When using a flame to heat a liquid in a test tube, which one is NOTsafe A.
the test tube is open (no rubber stopper)
B.
the open end is pointed away from you and your lab partner
C.
the test tube is closed with a rubber stopper
D.
the hot tube must be cooled before placing it into an ice bucket

Abullet found at a crime scene may be used as evidence in a trial if the percentage of metals match to the composition of metals in a bullet from the suspect's ammunition. a forensic scientist's analysis of the bullet shows that it contains 11.9 g of lead, 0.5 g of tin, and 0.8 b of antimony. what is the percentage of lead metal in the bullet? express your answers to the one's place.

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

200. ml of 3.00 m nacl solution is diluted to a final volume of 500. ml. what is the molarity of the final solution?