If the chemical properties of a substance have not changed , has a chemical reaction occurred

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.

Evaluate this exponential expression,8. (2 + 3)2 – 42

If a solution had a ph of 7 what is the solution