Catalysts

The idea

Catalysts are substances that cause a reaction to occur or proceed at a different rate.

Helpers in a reaction

Unsaturated hydrocarbons add hydrogen when palladium or nickel is present. Esters form from an acid and an alcohol when an acid catalyst is present.

What do you think a catalyst does?

• It causes the reaction to occur or proceed at a different rate
• It is the main product of the reaction
• It is the gas that is added

Catalyst or reactant?

Sort each substance from the book's reactions.

Catalysts change the rate

A catalyst is present in the reaction and makes it occur, or proceed at a different rate. In the book it appears as nickel, palladium or an acid.

Catalysts are substances that cause a reaction to occur or proceed at a different rate.

Notes

Catalysts are substances that cause a reaction to occur or proceed at a different rate.

Check yourself

What is a catalyst?

In the hydrogenation of vegetable oils, which substance is the catalyst?

Which of these are named as catalysts in the book?

Which substance is a catalyst when an acid and an alcohol form an ester?

• The unsaturated hydrocarbon that is being changed. That is a reactant. A catalyst causes a reaction to occur or proceed at a different rate.
• The gas that is added in the reaction. Hydrogen is a reactant that is added. A catalyst causes a reaction to occur or proceed at a different rate.
• A substance that causes a reaction to occur or proceed at a different rate — correct. Yes!
• Nickel — correct. Yes!
• Hydrogen. Hydrogen is added to the oil, so it is a reactant.
• The vegetable oil. The vegetable oil is the substance being hydrogenated, so it is a reactant.
• Ethene and ethane. Ethene is the unsaturated hydrocarbon that adds hydrogen, and ethane is the product.
• Palladium and nickel — correct. Yes!
• Sodium and potassium. These metals are not named as catalysts in this chapter.
• Ethanol. Ethanol is one of the reactants.
• The ester. The ester is the product.
• An acid — correct. Yes!