Sally and john are learning all about chemical reactions. to explore chemical reactions, they have decided to investigate the amount of time it takes ice to become liquid water. which of the following is the best explanation for why a chemical reaction did not take place?

Ice melting is a physical change (not a chemical change). The atoms of the water are not changing, but the physical state of the water is.

Physical change: ice melting
Chemical change: hydrogen and oxygen coming together to make H2O

The atomic weight of X is 28.356 amu

Explanation:

Step 1: Data given

X-28 has an isotopic mass of 27.979 u and an baundance of 77.11%

X-29 has an isotopic mass of 28.976 u and an baundance of 8.00 %

X-30 has an isotopic mass of 29.974 u and an baundance of 14.89 %

Step 2:  Calculate the atomic weight of X.

Atomic weight of X = 27.979 * 0.7711 + 0.28.976 * 0.08 + 29.974 *0.1489

Atomic weight of X = 28.356 amu

The atomic weight of X is 28.356 amu