Answer:
525.1 g of BaSO₄ are produced.
Explanation:
The reaction of precipitation is:
Na₂SO₄ (aq) + BaCl₂ (aq) → BaSO₄ (s) ↓ + 2NaCl (aq)
Ratio is 1:1. So 1 mol of sodium sulfate can make precipitate 1 mol of barium sulfate.
The excersise determines that the excess is the BaCl₂.
After the reaction goes complete and, at 100 % yield reaction, 2.25 moles of BaSO₄ are produced.
We convert the moles to mass: 2.25 mol . 233.38 g/mol = 525.1 g
The precipitation's equilibrium is:
SO₄⁻² (aq) + Ba²⁺ (aq) ⇄ BaSO₄ (s) ↓ Kps
<span> Au</span>₂(SeO₄)₃
O = -2 × 4 = -8
Se = + 6
So,
(+6 - 8) = -2
Means (SeO₄) contains -2 charge, Now multiply -2 by 3
-2 ₓ 3 = -6
Means,
Au₂ + (-6) = 0
Au₂ = +6
Or,
Au = 6 / 2
Au = +3
Result:
Au = +3
Se = +6
O = -2
Ni(CN)₂
Cyanide (CN⁻) contains -1 charge,
So,
N = -3
C = +2
Then,
Ni + (-1)₂ = 0
Ni - 2 = 0
Or,
Ni = +2
Result:
N = -3
C = +2
Ni = +2
Answer
B. acid + base --> salt + water
Explanation
Acids are substances that dissolve in water to produce hydrogen ions, H+.A base is a substance that dissolves in water to produce hydroxide ions, OH-.In a chemical reaction of an acid and a base, the products are a salt and water.For example when hydrocholoric acid is added to sodium hydroxide, a salt namely sodium chloride is formed with additional water.
The answers would be the mass before a reaction is the same as the mass after a reaction which basically means mass is conserved
