3rd one sorry if it’s wrong
CuCl2 + 2NaNO3 ----> Cu(NO3)2 + 2NaCl
using molar masses:-
Theoretical yields:-
63.54 + 2(35.45) g of CuCl2 produces 2(22.98 + 35.45) g of NaCl
134.44 g .................................................... 116.86 g
31.0 g ....................................................31.0 * 116.86 /134.44=26.95g
So percentage yield is 21.2* 100 / 26.95 = 78.7% to nearest tenth
Answer:
DNA
Explanation: Because if you stretch DNA it gets longer.
I would say it is a chemical change because after a while, the nails start to rust. Now they only rust after about a week though. But rust is a chemical change.
