Answer:
Phase transition is when a substance changes from a solid, liquid, or gas state to a different state. Every element and substance can transition from one phase to another at a specific combination of temperature and pressure.
Explanation:
<span>Mass Number = (Atomic Number) + (Number of Neutrons) so you solve for the Number of Neutrons and you get:
Number of Neutrons = (Mass number) - (Atomic Number)
Mass Number equals protons plus neutrons, round atomic weight to nearest whole number
Atomic Number equals number of Protons</span>
81.9 % is the percent yield of reaction of zinc with iodine producing ZnI2.
Explanation:
Balanced chemical equation for the reaction:
Zn + I2 ⇒ ZnI2
Data given:
mass of sample zinc = 129 grams
mass of ZnI2 formed = 510.6 grams (actual yield)
number of moles = 
number of moles of zinc = 
= 1.97 moles
from stoichiometry
1 mole of Zn reacts to form 1 mole of ZnI2
1.97 moles of Zn will form 1.97 moles of ZnI2
atomic mass of ZnI2 = 319.22 grams/mole
mass of ZnI2 formed = 628.86 grams (theoretical yield)
% yield =
x100 equation 1
from the reaction,
Putting the values in equation 1
% yield =
x 100
= 81.19 % is the % yield.
Answer:
endothermic
Explanation:
Heat is added to make the process possible.
Answer:
- <em>There are </em><u><em>4 moles</em></u><em> of chloride ions in 2 moles of calcium chloride.</em>
Explanation:
Start by writing the chemical formula of calcium chloride.
The suffix -ide in chloride means that chlorine is working as the ion Cl⁻, this is with oxidation state -1.
Calcium, being an alkaline earth metal, uses oxidation state +2, Ca²⁺
Then, two atoms of Cl are combined with one atom of calcium, because in this way each Cl atom will accept one electron from a Ca atom, which will donate its two valence electrons.
That is indicated in the chemical formula with subscripts: <u><em>CaCl₂</em></u>, meaning that each formula-unit of calcium chloride has 2 ions of chlorine and 1 ions of calcium, or twice the number of moles of chloride ion.
- 1 mol CaCl₂ : 1 mol Ca⁺ : 2 mol Cl⁻
⇒ 2 mol CaCl₂ : 2 mol Ca⁺ : 4 mol Cl⁻
Hence, there are 4 moles of chloride ions in 2 moles of calcium chloride.