1) B, Not 100% sure though
2)Building a rocket is a physical change technically its not changing its composition its just changing its appearance, the fuel for it causes a chemical change, there is an answer that is more clear, Grinding chalk into a fine powder only changes its shape which is a physical change.
I think it's D but not sure
<h3>The average atomic mass of Iodine : 126.86 amu</h3><h3>Further explanation</h3>
Given
80% 127I, 17% 126I, and 3% 128I.
Required
The average atomic mass
Solution
The elements in nature have several types of isotopes
Atomic mass is the average atomic mass of all its isotopes
Mass atom X = mass isotope 1 . % + mass isotope 2.% + ... mass isotope n.%
Atomic mass of Iodine = 0.8 x 127 + 0.17 x 126 + 0.03 x 128
Atomic mass of Iodine = 101.6 + 21.42 + 3.84
Atomic mass of Iodine = 126.86 amu
The correct answer that would best complete the given statement above is option B. Heat in a substance is an example of a kinetic energy. Kinetic energy is a kind of energy that is in motion. We can feel the kinetic energy of heat through their temperatures because heat is being transferred.
Answer:
7
Explanation:
N-14 has 7
i looked it up ye ur probably gonna get it right
