Answer:
135g Na2CO3
Explanation:
I'm going to assume you mean Molality which is mol solute/kg solvent
Molarity would be mol soute/ L solution
we know we have 155g of water which is .155 kg
essentially we have the equation:
mol/kg = 8.20
we substitute .155 in for kg and get:
mol/.155 = 8.20
Solving this gives mol = 1.271
now we must convert to grams using the molar mass
Molar mass Na2CO3 = 106G/mol
so to cancel moles we multiply:
1.271mol x 106g/mol
= 135g
Answer:
The answer to your question is 0.269 g of Pb
Explanation:
Data
Lead solution = 0.000013 M
Volume = 100 L
mass = 0.269 g
atomic mass Pb = 207.2 g
Chemical reaction
2Pb(s) + O₂(aq) + 4H⁺(aq) → 2H₂O(l) + 2Pb₂⁺(aq)
Process
1.- Calculate the mass of Pb in solution
Formula
Molarity = 
Solve for number of moles
Number of moles = Volume x Molarity
Substitution
Number of moles = 100 x 0.000013
Number of moles = 0.0013
2.- Calculate the mass of Pb formed.
207.2 g of Pb ----------------- 1 mol
x g ----------------- 0.0013 moles
x = (0.0013 x 207.2) / 1
x = 0.269 g of Pb
Answer:The model states that electrons in atoms move in circular orbits around a central nucleus and can only orbit stably in certain fixed circular orbits at a discrete set of distances from the nucleus. These orbits are associated with definite energies and are also called energy shells or energy levels.
bohrs model and other models are really hard to understand but i hope this will help you!
Answer:
I believe the answer would be A
Helium
Remember: electron filling of atomic shell ...
The element which have electron in the lowest quantum shell will have the smallest atomic radius\
He:1s1 (Helium)
H:1s2 (hydrogen)
