When other scientists repeat experiments and come up with the same results it validates it and show that the answers are true
Since the chemical formula is Al2O3, it means in a single molecule there are 2 atoms Al and 3 atoms O. O means oxygen and Al means alluminium, so there are 2 atoms alluminium and 3 atoms oxygen.
Answer:
0.218 M of Pb(NO3)2
Explanation:
Equation of the reaction
Pb(NO3)2(aq) + 2NaCl(aq) --> PbCl2(s) + 2NaNO3(aq)
1 mole of Pb(NO3)2 reacts to precipitate 1 mole of PbCl2
Molar mass of PbCl2 = 207 + (35.5*2)
= 278 g/mol
Number of moles of PbCl2 precipitated = mass/molar mass
= 12.11/278
= 0.04356 mol
Since 0.04356 moles of PbCl2 was precipitated, therefore by stoichiometry; 0.04356 moles of Pb(NO3)2 reacted.
Molarity is defined as the number of moles of solute in 1 liter of solution.
Molarity = number of moles/volumes
= 0.04356/0.2
= 0.218 M
The chemical equation is said to be balanced if the number of atoms in the reactants and products is the same
<h3>Further explanation</h3>
Equation balanced ⇒ total number of atoms in reactants(on the left)= total number of atoms in products(on the right)
H₂+O₂---> H₂O
Reactants : H₂, O₂
Products : H₂O
not balanced
H₂O₂ ---> H₂O+O₂
Reactants : H₂O₂
Products : H₂O, O₂
not balanced
Na+O₂ ---> Na₂O
Reactants : Na, O₂
Products : Na₂O
not balanced
N₂+H₂ ---> NH₃
Reactants : N₂, H₂
Products : NH₃
not balanced
P₄+O₂---> P₄O₁₀
Reactants : P₄, O₂
Products : P₄O₁₀
not balanced
Fe+H₂O ----> Fe₃O₄ + H₂
Reactants : Fe, H₂O
Products : Fe₃O₄
not balanced
