Answer:
2.55 moles of NaOH are needed react with 500.0 gram of H₂SO₄.
Explanation:
Given data:
Mass of H₂SO₄ = 500.0 g
Number of moles of NaOH needed = ?
Solution:
H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
Number of moles of H₂SO₄:
Number of moles = mass/molar mass
Number of moles = 500.0 g/ 98.07 g/mol
Number of moles = 5.09 mol
Now we will compare the moles of H₂SO₄ and NaOH.
H₂SO₄ : NaOH
1 : 2
5.09 : 1/2×5.09 = 2.55 mol
Thus, 2.55 moles of NaOH are needed react with 500.0 gram of H₂SO₄.
You could ask whether the black crust is a new substance formed from silver underwent a chemical change because a chemical change produces a new substance.
Answer:
92.87 g.
Explanation:
∵ The percentage yield = (actual yield/theoretical yield)*100.
- We need to calculate the theoretical yield:
From the balanced reaction:
<em>PCl₃ + Cl₂ → PCl₅,</em>
It is clear that 1 mol of PCl₃ reacts with 1 mol of Cl₂ to produce 1 mol of PCl₅.
- We need to calculate the no. of moles of 73.7 g PCl₃:
n = mass/molar mass = (73.7 g)/(137.33 g/mol) = 0.536 mol.
<u><em>Using cross multiplication:</em></u>
1 mol of PCl₃ produce → 1 mol of PCl₅, from stichiometry.
∴ 0.536 mol of PCl₃ produce → 0.536 mol of PCl₅.
∴ The mass of PCl₅ (theoretical yield) = (no. of moles) * (molar mass) = (0.536 mol)*(208.24 g/mol) = 111.62 g.
<em>∵ The percentage yield = (actual yield/theoretical yield)*100.</em>
The percentage yield = 83.2%, theoretical yield = 111.62 g.
∴ The actual yield of PCl₅ = (The percentage yield)(theoretical yield)/100 = (83.2%)(111.62 g)/100 = 92.87 g.
Answer:
63.616
Explanation:
DATA
1. first atomic mass;m1=63
- second atomic mass;m2=65
- first percentage;p1= 69.2%
- second percentage me;p2=30.8%
- average mass;avg= ?
SOLUTION
avg=<u> (m1)(p1) + (m2)(</u><u>p2</u><u>)</u>
100
avg= <u>(63)(69.2) + (65)(30.8)</u>
100
avg= <u>4</u><u>3</u><u>5</u><u>9</u><u>.</u><u>6</u><u> </u><u>+</u><u> </u><u>2</u><u>0</u><u>0</u><u>2</u>
100
avg= <u>6361.6</u>
100
avg= 63.616
Heat flows from our body to iron