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Questions
Write two factors that affect the rate of reaction.
List the factors affecting the rate of reaction.
Explain briefly the various factors which affect the rate of a reaction.
On what factors does the rate of a reaction depend?
List any two factors that influence the rate of chemical reaction. Indicate whether the rate constant of the reaction is dependent on or independent of these factors.
Mention any two factors that influence the rate of a chemical reaction.
Mention the factors that affect the rate of a chemical reaction.
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Solution
- Nature of reactants: The makeup of the reactants affects how quickly a chemical reaction proceeds. For instance, reactions involving polar and ionic chemicals proceed fairly quickly, while those involving covalent compounds proceed considerably more slowly. Because the electrostatic interactions in their molecules are readily disrupted in aqueous solutions, reactions involving polar or ionic compounds proceed relatively quickly. Old bonds are broken and new bonds are formed, or the bonds are rearranged, in a chemical reaction involving covalent reactants. As a result, the rate of a reaction involving the rearrangement of bonds is determined by how easily the particular bonds are made or broken. For example, nitric oxide oxidises to nitrogen peroxide far more quickly than carbon monoxide oxidises to carbon dioxide. The two responses seem to be comparable.
\[\ce{2NO_{(g)} + O2_{(g)} -> 2NO2_{(g)} (fast)}\]
\[\ce{2CO_{(g)} + O2 -> 2CO2_{(g)} (slow)}\]
Because of variations in the energies required for the reactants' bond rearrangement, these two reactions have different speeds. - Concentration of reactants: In general, a reaction's rate rises as the reactant concentration does. Molecular collisions are more likely to occur when a reactant's concentration rises. As a result, the reaction rate rises.
- Temperature: Reaction rates typically rise with temperature. For most homogeneous reactions, increasing the temperature by 10° doubles or triples the rate. Temperature significantly affects reaction rates.
- Surface area: Solid reactants have a higher rate of reaction as their surface area increases. Finely split solid reactants have a higher surface area than huge reactants and react faster. For instance, powdered coal burns faster than lump coal.
Increasing the surface area of a solid reactant improves the contact area between two reactants. This increases the pace of molecular interactions, leading to faster reactions. - Presence of a catalyst: A catalyst is a material that speeds up a reaction while maintaining its amount and chemical makeup.
A catalyst accelerates the rate of a reaction. This is because it offers a less energy-intensive alternate path. Lowering the energy barrier allows more molecules of reactants to cross it. As a result, the rate of reaction rises.
The rate constant depends on the nature of the reactants, temperature, and catalyst, and it is independent of concentration and surface area.
Notes
Students should refer to the answer according to their question.
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OR
The half-life for radioactive decay of 14C is 6930 years. An archaeological artifact containing wood had only 75% of the 14C found in a living tree. Find the age of the sample.
[log 4 = 0.6021, log 3 = 0.4771, log 2 = 0.3010, log 10 = 1] [2]
The following data was obtained for chemical reaction given below at 975 K.
\[\ce{2NO(g) + 2H2(g) -> N2(g) + 2H2O(g)}\]
| [NO] | [H2] | Rate | |
| Mol L-1 | Mol L-1 | Mol L-1 s-1 | |
| (1) | 8 × 10-5 | 8 × 10-5 | 7 × 10-9 |
| (2) | 24 × 10-5 | 8 × 10-5 | 2.1 × 10-8 |
| (3) | 24 × 10-5 | 32 × 10-5 | 8.4 × 10-8 |
The order of the reaction with respect to NO is ______. (Integer answer)
Which of the following statement is true?
