Answer:
C
Explanation:
The ball is undergoing a gravitational potential to kinetic energy transformation. When the ball is at the top of the slope, it has the potential to be moved down by gravity, hence the name. When it's rolling down the slope, it turns to kinetic energy, which is when something moves.
Answer:
94.4g/mol is molar mass of the unknown
Explanation:
Based on the freezing point depression equation:
ΔT = Kf*m*i
<em>Where ΔT is the depression in freezing point (1.87°C)</em>
<em>Kf is freezing point depression constant of water (1.86°Ckg/mol)</em>
<em>And i is Van't Hoff factor (1 for nonelectrolyte solutes)</em>
<em />
Replacing:
1.87°C = 1.86°CKg/mol*m*i
1.005mol/kg solvent = m
Using the mass of the solvent we can find the oles of the nonelectrolyte:
1.005mol/kg solvent * 0.4764kg = 0.479moles
Molar mass is defined as the ratio between mass of a substance in grams and moles, that is:
45.2g / 0.479mol =
<h3>94.4g/mol is molar mass of the unknown</h3>
Answer:
Mass = 17.12 g
Explanation:
Given data:
Mass of Al = 3.90 g
Mass of H₂SO₄ = 13.65
Mass of aluminium sulfate = ?
Solution:
Chemical equation:
3H₂SO₄ + 2Al → Al₂(SO₄)₃ + 3H₂
Now we will calculate the number of moles of each reactant.
Moles of H₂SO₄:
Number of moles = mass/ molar mass
Number of moles = 13.65 g/ 98.079 g/mol
Number of moles = 0.14 mol
Moles of Al:
Number of moles = mass/ molar mass
Number of moles = 3.90 g/ 27 g/mol
Number of moles = 0.14 mol
Now we will compare the moles of aluminium sulfate with sulfuric acid and aluminium.
H₂SO₄ : Al₂(SO₄)₃
3 : 1
0.14 : 1/3×0.14 = 0.05
Al : Al₂(SO₄)₃
2 : 1
0.14 : 1/2×0.14 = 0.07
The number of moles of aluminium sulfate produced by sulfuric acid are less so it will limiting reactant and limit the amount of aluminium sulfate.
Mass of aluminium sulfate:
Mass = number of moles × molar mass
Mass = 0.05 mol × 342.15 g/mol
Mass = 17.12 g