energetics and kinetics

Which reaction is endothermic?

• acid neutralising alkali causing a temperature increase

• adding magnesium to hydrochloric acid

• calcium carbonate decomposing when heated combustion of fossil fuels

Which statements about exothermic and endothermic reactions are correct?

• During an exothermic reaction, heat is given out

• The temperature of an endothermic reaction goes up because heat is taken in

• Burning methane in the air is an exothermic reaction

Which is an endothermic process?

• Burning hydrogen

• Distilling petroleum

• Reacting potassium with water

• Using petrol in a motor car engine

Which fuel does not produce carbon dioxide when it burns?

• Coal

• Hydrogen

• Methane

Statement 1 Hydrogen is used as a fuel.

Statement 2 When hydrogen burns in the air to form water, heat energy is produced.

Which is correct?

• Both statements are correct and statement 2 explains statement 1

• Both statements are correct but statement 2 does not explain statement 1

• C Statement 1 is correct but statement 2 is incorrect

Some white anhydrous copper(II) sulfate powder is put into a beaker of water and stirred. What would show that the process was exothermic?

• A blue solution is formed

• The beaker feels cooler

• The beaker feels warmer

Which of the following is true about the formation of bonds between molecules?

• Energy is given off when bonds are formed between molecules.

• Energy is absorbed by the molecule when bonds are formed.

• Energy is neither given off nor absorbed when bonds are formed.

Which of the following statement is true about the breaking of bonds between molecules?

• To break a bond between molecules, energy must be released by the molecule

• To break a bond between molecules, no energy is needed.

• To break a bond between molecules, energy must be absorbed by the molecule.

Which letter corresponds to the energy of the products?

• A
• B
• C
• D

If ∆H is negative, the reaction is?

• exothermic
• endothermic