Statement 2 is correct.
solids moving into solution is a physical change as the core structure of the molecules remain the same. evaporation of water and crystallization of salt are both physical changes as well.
The water does not change it's H2O chemical makeup because salt was dissolved into it.
Is it asking which is or isn’t balanced
The charge would be -2 because there are 2 more electrons than protons, and electrons have a negative charge.
Answer:
30moles of SiO₂
Explanation:
Given parameters:
Number of moles of O₂ = 30moles
Unknown:
Number of moles of SiO₂ = ?
Solution:
To solve this problem, we need to write the reaction expression:
Si + O₂ → SiO₂
The reaction is balanced;
1 mole of O₂ will produce 1 mole of SiO₂
30mole of O₂ will produce 30moles of SiO₂
Data: molar mass 470 g/mol
Percent composition:
Hg = 85.0%
Cl = 15.0%
Solution:
1) Convert % to molar ratios
A. Base: 100 g
=> Hg = 85.0 g / 200.59 g/mol = 0.4235 mol
Cl = 15.0 g / 35.45 g/mol = 0.4231 mol
B. divide by the higher number and round to whole number
Hg = 0.4325 / 0.4231 = 1.00
Cl = 0.4231 / 0.4231 = 1.00
=> Empirical formula = Hg Cl
2) Find the mass of the empirical formula:
HgCl: 200.59 g/mol + 35.45 g/mol = 236.04
3) Determine how many times is the empirical mass contained in the molecular mass:
470 g/mol / 236.04 = 1.99 ≈ 2
=> Molecular formula = Hg2 Cl2.
Answers:
Empirical formula HgCl
Molecular Formula Hg2Cl2
