1s^2 2s^2 <span>is the electron configuration for an electrically neutral atom of beryllium(Be).</span>
Answer:
- 75.5 g O₂ (g) can be produced from 42.6 g of H₂O (g)
Explanation:
<u>1) Balanced chemical equation (given):</u>
<u>2) Mole ratios:</u>
- 2 moles H₂O(g) : 2 moles H₂(g) : 2 moles O₂(g)
<u>3) Calculate the number of moles of reactant (H₂0):</u>
- number of moles = mass in grams / molar mass
- molar mass of water: 18.015 g/mol
- mass in grams of water: 42.6 g
- number of moles = 42.6 g / 18.05 g/mol = 2.36 moles H₂O
<u>4) Set a proportion using the mole ratio O₂ to H₂O and the actual number of moles of H₂O:</u>
- 2 moles O₂ / 2 moles H₂O = x / 2.36 moles H₂O
<u>5) Convert 2.36 moles O₂ to grams:</u>
- mass in grams = number of moles × molar mass
- mass = 2.36 moles × 32.00 g/mol = 75.5 g O₂
Answer: The number of atoms remain constant and thus the mass also remains conserved.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
In product side ,
there are 2 atoms of potassium, 2 atoms of nitrogen and 6 oxygen atoms. In 
there is 1 atom of lead and 2 atoms of iodine.
In reactant side ,
there are 2 atoms of nitrogen, 6 oxygen atoms and 1 atom of lead. In 
there are 2 atoms of potassium and 2 atoms of iodine.
Thus the number of atoms remain constant and thus the mass also remains conserved.
