Pure silicon is a poor conductor at room temperature because it has 4 valence electrons
Answer:
Explanation:
<u>1) Balanced chemical equation:</u>
<u>2) Mole ratio:</u>
- 2 mol S : 3 mol O₂ : 2 mol SO₃
<u>3) Limiting reactant:</u>
n = 6.0 g / 32.0 g/mol = 0.1875 mol O₂
n = 7.0 g / 32.065 g/mol = 0.2183 mol S
Actual ratio: 0.1875 mol O₂ / 0.2183 mol S =0.859
Theoretical ratio: 3 mol O₂ / 2 mol S = 1.5
Since there is a smaller proportion of O₂ (0.859) than the theoretical ratio (1.5), O₂ will be used before all S be consumed, and O₂ is the limiting reactant.
<u>4) Calcuate theoretical yield (using the limiting reactant):</u>
- 0.1875 mol O₂ / x = 3 mol O₂ / 2 mol SO₃
- x = 0.1875 × 2 / 3 mol SO₃ = 0.125 mol SO₃
<u>5) Yield in grams:</u>
- mass = number of moles × molar mass = 0.125 mol × 80.06 g/mol = 10.0 g
<u>6) </u><em><u>Percent yield:</u></em>
- Percent yield, % = (actual yield / theoretical yield) × 100
- % = (7.9 g / 10.0 g) × 100 = 79%
Answer:
The rate of reaction increases when the reaction is catalyzed by using catalyst.
Explanation:
Catalyst is a specie which when involved in reaction, speeds up the reaction without consuming itself. The catalyst is regenerated at the end of reaction and is recovered in good yield. Catalyst main role in reaction is to decrease the Activation energy of the reaction. This decrease in activation is achieved through different mechanisms. Without going in detail, they are as follow,
1) By providing different pathway to reaction
2) By weakening the bonds
3) By providing surface area to reactants
A compressed spring would have mechanical energy cause it generates from the force being built up in the spring
