Answer:
154 kg
Explanation:
Step 1: Define conversion
1 kg = 2.20 lbs
Step 2: Use Dimensional Analysis
= 153.636 kg
Step 3: Simplify
We are give 3 sig figs.
153.636 kg ≈ 154 kg
The question says only to convert the Zn(OH)₂ into moles. But the given answer has many errors such as formula, mass and moles.
<span>The corrected answer is as follows.
</span>Moles (mol) = mass (g) / molar mass (g/mol)
<span>
</span><span>Mass of Zn(OH)₂</span><span> = 0.45 g
Molar mass of Zn(OH)₂ = </span><span>99.424 g/mol
</span>Hence, moles of Zn(OH)₂ = 0.45 g / 99.424 g/mol
<span> = 4.526 x 10⁻³ mol
</span>
Reaction.-
2H2 + O2 ---> 2H2O
Given,
Mass of Oxygen - 25.0 g
Mass of Hydrogen - 42.0 g
now we have to calculate moles
moles of O2 = 25/16 = 1.5625 moles
Moles of H2 = 42/2 = 21 moles
Hydrogen gas is in excess,
now using reaction
1 mole of oxygen gas forms 2 moles of H2O
1.5625 mole of Oxygen gas will form x mole of H20
x = 3.125 moles
molar mass of H2O is 18g
mass of 3.125moles of water = 3.125 × 18 = 56.25 g.
Hence the mass of water produced when 25.0g of oxygen gas react with 42.0g of hydrogen gas is 56.25 grams
