How can we speed up or slow down a reaction?

• The rate of a chemical reaction can be speeded up or slowed down by changing the temperature.
• Other ways of changing the rate of the Chemical Reactions are, by stirring them and/or changing the size or concentration of the reactants.

In order for a reaction to occur, there must be a collision between the reactants at the reactive site of the molecule. In general, the reaction rate is slower when the reactants are large and complex molecules.

Reactant concentration, the physical state of the reactants, and surface area, temperature, and the presence of a catalyst are the four main factors that affect reaction rate.

You can also determine which reaction is fast and which reaction is slow if you are given the rate law. Which ever reactants are present in the rate law are the reactants in the slow reaction.

Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.

Seven top tips to improve your reflexes

1. Pick a sport, any sport – and practise. What exactly do you want to improve your reflexes for?
2. Chill out.
3. Eat a lot of spinach and eggs.
4. Play more video games (no, really)
5. Use your loose change.
6. Playing ball.
7. Make sure you get enough sleep.

Calculate the enthalpy of reaction (ΔH) If ΔH is negative (−) then the chemical reaction is exothermic, because more energy is released when the products are formed than energy is used to break up the reactants.

Reactions in phases that easily mix, such as gases and liquids, occur much faster than reactions between solids. The extent of mixing of the reactants influences the frequency of molecular collisions – if reactants are more thoroughly mixed, the molecules will collide more often and thus react faster.

There are four main factors that can affect the reaction rate of a chemical reaction:

• Reactant concentration. Increasing the concentration of one or more reactants will often increase the rate of reaction.
• Physical state of the reactants and surface area.
• Temperature.
• Presence of a catalyst.

Answer. Answer: it is depend on the concentration of the reactants, the exposed surface area of the reactant (only for solid) , temperature, pressure, ( only for gas ) and if there is a catalyst present in the reaction. if concentration increase, rate of reaction increase.

SN2 take place faster . its a one steped process . and SN 1 is two steped process in which first step that is formation of carbcation is slow and second step that is attack of nucleophile is fast .

Sn1 is a unimolecular reaction while Sn2 is a bimolecular reaction….Difference Between Sn1 and Sn2:

Explanation: SN2 reactions involve a backside nucleophilic attack on an electrophilic carbon. As a result, less steric congestion for this backside attack results in a faster reaction, meaning that SN2 reactions proceed fastest for primary carbons.

The key factors that determine the nucleophile’s strength are charge, electronegativity, steric hindrance, and nature of the solvent. Nucleophilicity increases as the density of negative charge increases.

like you said Br- is bigger than Cl- and can therefore better stabilize the negative charge, making it a better leaving group.

SN1 reactions happen in two steps: 1. The leaving group leaves, and the substrate forms a carbocation intermediate. The nucleophile attacks the carbocation, forming the product.

Molecule that will react the fastest in an SN1 reaction is 1 while the slowest is 5.

The SN1 reaction is a substitution reaction in organic chemistry, the name of which refers to the Hughes-Ingold symbol of the mechanism. “SN” stands for “nucleophilic substitution”, and the “1” says that the rate-determining step is unimolecular.

SN1 reactions are important because, as far as we know, they describe a mechanism of organic reactivity, of chemical reactivity. And they describe a BOND-BREAKING PROCESS, as compared to SN2 reactions, which are bond-making processes with respect to the rate determining step.

The hydrolysis of tert-butyl bromide with aqueous NaOH solution is an example of SN1 reaction. The rate of the reaction depends on the concentration of tert butyl bromide but it is independent of the concentration of NaOH. Hence, the rate determining step only involves tert-butyl bromide.

The higher the temperature, the faster a non-biological reaction tends to occur. For SN1 and SN2 reactions, the higher the temperature, the more elimination products you get. The more elimination products you get, since the amount of reactant is limited, the less substitution products you get, as well.

Racemization occurs when one pure form of an enantiomer is converted into equal proportion of both enantiomers, forming a racemate. When there are both equal numbers of dextrorotating and levorotating molecules, the net optical rotation of a racemate is zero.

Adding HOBt, 6-Cl-HOBt or HOAt suppresses the racemization. Histidine and cysteine are especially prone to racemization. Protecting the pi imidazole nitrogen in the histidine side-chain with the methoxybenzyl group greatly reduces racemization.

When equal amounts of d− isomer and l− isomer are mixed one gets a ” racemic mixture” and this process is called racemisation. For example, when equal amounts of d− tartaric acid and l− tartaric acid are mixed, we get racemic tartaric acid which is opticalled inactive mixture.

When equal amounts of dextrorotatory and laevorotatory isomers are mixed then the resulting mixture becomes optically inactive because optical activities of each isomer cancel each other. Such a mixture is called a racemic mixture and this phenomenon is called racemization.

Each enantiomer rotates the plane of polarization of plane-polarized light through a characteristic angle, but, because the rotatory effect of each component exactly cancels that of the other, the racemic mixture is optically inactive. …

If you increase the concentration of a reactant, there will be more of the chemical present. More reactant particles moving together allow more collisions to happen and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.

Complete answer: The slow reaction possesses a low rate of reaction. They possess higher activation energy. The example of slow reactions are rusting of a water pipe, a piece of newspaper turning yellow and so forth. The fast reaction is defined as the reaction which takes a shorter time to complete.

Changes in concentration, temperature, and pressure can affect the position of equilibrium of a reversible reaction. Chemical reactions are equilibrium reactions. Equilibrium occurs when a certain proportion of a mixture exists as reactants and the rest exits as products.

A reaction inhibitor is a substance that decreases the rate of, or prevents, a chemical reaction. A catalyst, in contrast, is a substance that increases the rate of a chemical reaction.

Catalysis is the change in speed (rate) of a chemical reaction due to the help of a catalyst. A catalyst may participate in many chemical reactions. Catalysts that speed the reaction are called positive catalysts. Catalysts that slow the reaction are called negative catalysts, or inhibitors.

Avoid storing incompatible chemicals together. Keep all chemicals, especially flammables, oxidizers, reactives, and organic peroxides, away from heat and ignition sources. Use administrative and engineered controls before resorting to personal protective equipment (PPE) for worker protection.

“Without catalysts, there would be no life at all, from microbes to humans,” he said. “It makes you wonder how natural selection operated in such a way as to produce a protein that got off the ground as a primitive catalyst for such an extraordinarily slow reaction.”

Key points. A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process. Catalysts typically speed up a reaction by reducing the activation energy or changing the reaction mechanism. Enzymes are proteins that act as catalysts in biochemical reactions.