1. Physical
2. D
3. It’s either A or D but I think it’s A
4. C
5. A
6. D
7. A
8. B
9. I couldn’t see the question for it
10. A
11. D
12. D
13. B
The answer would be C. charge because the protons, which are positively charged particles, and the electrons, negatively charged particles, balance each other out and the atom becomes of a neutral charge (or no charge)
Explanation:
To balance this chemical equation-
see
Balanced form:-
CaO + 2 HCl ==. CaCl2 + H2O
.
Answer:
(c) only Ca2+(aq) and Hg2+(aq)
Explanation:
- In the first step, hydrochloric acid (HCl) is added to the solution. In this case the equilibrium that could take place is:
Ag⁺(aq) + Cl⁻(aq) ↔ AgCl(s)
But no precipitate was formed, so Ag⁺(aq) is absent.
- By adding H₂SO₄(aq) the next equilibrium that could take place is:
Ca⁺²(aq) + SO₄⁻²(aq) ↔ CaSO₄(s)
A white precipitate was formed, so Ca⁺² is present in the solution.
- The following could take place after adding H₂S(aq):
Hg²⁺(aq) + S⁻² ↔ HgS(s)
A black precipitate formed, so Hg⁺² is present as well.
Answer:
mole fraction of NaCl = 0.03145.
mole fraction of water = 0.9686.
Explanation:
- Mole fraction is an expression of the concentration of a solution or mixture.
- It is equal to the moles of one component divided by the total moles in the solution or mixture.
- The summation of mole fraction of all mixture components = 1.
mole fraction of NaCl = (no. of moles of NaCl) / (total no. of moles).
<em>no. of moles of NaCl = mass/molar mass </em>= (6.87 g)/(58.44 g/mol) = 0.1176 mol.
<em>no. of moles of water = mass/molar mass</em> = (65.2 g)/(18.0 g/mol) = <em>3.622 mol.</em>
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∴ mole fraction of NaCl = (no. of moles of NaCl) / (total no. of moles) = (0.1176 mol)/(0.1176 mol + 3.622 mol) = 0.03145.
<em>∵ mole fraction of NaCl + mole fraction of water = 1.0.</em>
∴ mole fraction of water = 1.0 - mole fraction of NaCl = 1.0 - 0.03145 = 0.9686.
