Answer:
3.49 g
Explanation:
The mass is the product of volume and density:
(8.96 g/cm³)(0.39 cm³) ≈ 3.49 g
The mass of a pure-copper penny would be 3.49 g.
In the presence of heat, copper (II) hydroxide decomposes in to copper (II) oxide.
Cu(OH)₂ (s) ----> CuO (s) + H₂O (l)
upon decomposition, water is removed from Cu(OH)₂
the amount of Cu(OH)₂ decomposed - 3.67 g
number of moles of Cu(OH)₂ - 3.67 g / 97.5 g/mol = 0.038 mol
stoichiometry of Cu(OH)₂ to CuO is 1:1
therefore number of CuO moles formed are - 0.038 mol
CuO reacts with sulfuric acid to form CuSO₄
CuO + H₂SO₄ ---> CuSO₄ + H₂O
stoichiometry of CuO to H₂SO₄ is 1:1
therefore number of H₂SO₄ moles that should react is 0.038 mol
the molarity of H₂SO₄ is 3M
this means that in 1000 ml - 3 mol of H₂SO₄ present
so if 3 mol are present in 1000 ml
then volume for 0.038 mol = 1000/3 * 0.038
= 12.67 ml
Answer:
5
Explanation:
A lithium atom with an atomic number of 3 and a charge of -2 will have a total number of electrons.
The atomic number is the number of protons in an atom. For a neutral atom that has not gained or lost electrons, the atomic number is the same as the number of electrons.
neutral atom: atomic number of electrons
For neutral atom of lithium, we will have 3 electrons
Now, lithium with a charge of -2 has gained two more electrons to the original 3 this now makes it 5.
ii.
It is an anion because it is negatively charged.
Negatively charged particles are called anion.
Answer:
B: Adding water, then adding solute
Explanation:
This is because, say you have a solution with a certain concentration.
If you add more water, it will become more diluted (less concentrated)
If you add more solute, it will become more concentrated.
Therefore if you add water and solute, it could cancel out, and the concentration would remain the same.
Hope this helps! Let me know if you have any questions/ would like anything further explained :)
