There are several differences between a physical and chemical change in matter or substances. A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
1. A mixture of ammonium chloride, sand, and zinc chloride should be separated by sublimation.
2. A mixture of zinc chloride and silver chloride should be separated through crystallization.
<h3>What is a separation technique?</h3>
A separation technique can be defined as a technique that is typically used to separate or convert two (2) or more mixture and solution of chemical substances into distinct product such as chemical compounds or elements.
<h3>The types of
separation technique.</h3>
In Chemistry, there are various types of separation technique used for the separation of mixtures or solutions and these include:
In this scenario, the most effective and efficient means to separate a mixture of ammonium chloride, sand, and zinc chloride is by sublimation from solid to gas state.
On the other hand, the best means to separate a mixture of zinc chloride and silver chloride is through crystallization.
Read more on crystallization here: brainly.com/question/4980962
The answer is: Dividing the number of molecules in the sample by Avogadro's number.
The Avogadro’s number is the number of atoms in 12 grams of the isotope carbon-12 (¹²C).
Na is Avogadro number or Avogadro constant (the number of particles, in this example carbon, that are contained in the amount of substance given by one mole).
The Avogadro number has value 6.022·10²³ 1/mol in the International System of Units; Na = 6.022·10²³ 1/mol.
For example:
N(Ba) = 2.62·10²³; number of atoms of barium.
n(Ba) = N(Ba) ÷ Na.
n(Ba) = 1.3·10²⁴ ÷ 6.022·10²³ 1/mol.
n(Ba) = 2.158 mol; amount of substance of barium.
Answer:
number of valence electrons
Explanation:
All of the elements in group 17, also known as group 7A, have 7 valence electrons.
No two elements have the same atomic number nor atomic mass in elemental form.
Halogens may have any number of isotopes.
