1. to calculate molar mass , you need average atomic mass of each element.
formula is simple
suppose we have Na2CO3
here it says
there are
2 atoms of Na
1 atom of C
3 atom of O
now
molar mass = (total atoms of Na × average atomic mass of Na) + ( total atom of C × average atomic mass of C )+ (total atom of O × average atomic mass of O)
i hope you can figure out it now.
in case of (NH4)2
this means you have 2 count of NH4
so total atoms of N = 2
total atoms of H = 4×2 = 8
so on you can now figure it out
2. balanced equation
here LHS and RHS shoild have same number of atoms of each element .
for example
H2 + Cl2 => 2HCl
here 2 atoms of H combined with 2 atoms of Cl , we know H and Cl combined and formed HCl now because total H atoms are 2 and Cl atoms are 2 in LHS then we should also have 2 atoms of each in right side
so thats why we have 2HCl in right side.
Try to figure out . let me know if need any help
Answer:
Dark Matter
Explanation:
90 percent of the mass in the universe is dark matter
Answer:
5.645 × 10⁻²³ g
Solution:
Step 1) Calculate Molar Mass of SH₂;
Atomic Mass of Sulfur = 32 g/mol
Atomic Mass of H₂ = 2 g/mol
--------------------
Molecular Mass of SH₂ = 34 g/mol
Step 2: Calculate mass of one molecule of SH₂ as;
As,
Moles = # of Molecules / 6.022 × 10²³
Also, Moles = Mass / M.Mass So,
Mass/M.mass = # of Molecules / 6.022 × 10²³
Solving for Mass,
Mass = # of Molecules × M.mass / 6.022 × 10²³
Putting values,
Mass = (1 Molecule × 34 g.mol⁻¹) ÷ 6.022 × 10²³
Mass = 5.645 × 10⁻²³ g
Answer:
Mole fraction H₂O → 0.72
Mole fraction C₂H₅OH → 0.28
Explanation:
By the mass of the two elements in the solution, we determine the moles of each:
25 g . 1 mol/ 18g = 1.39 moles of water (solute)
25 g . 1 mol / 46 g = 0.543 moles of ethanol (solvent)
Mole fraction solute = Moles of solute / Total moles
Mole fraction solvent = Moles of solvent / Total moles
Total moles = Moles of solute + Moles of solvent
1.39 moles of solute + 0.543 moles of solvent = 1.933 moles → Total moles
Mole fraction H₂O = 1.39 / 1.933 → 0.72
Mole fraction C₂H₅OH= 0.543 / 1.933 → 0.28
Remember that sum of mole fractions = 1
