Answer: Introduction
Did you know that flour can explode? Luckily, this does not happen spontaneously on your kitchen counter, but only if the conditions are right. You need a very fine powder of flour to make an explosion happen. In fact, any solid flammable material that is dispersed in the air as a dust cloud will explode if it comes into contact with flame (a reason extreme caution must be used where there is a large amount of grain dust, such as in storage facilities). Why is that? It has to do with the particle size of the solid material, which determines how rapidly a chemical reaction takes place. In this activity, you can try this for yourself—skipping the explosion and creating a big fizz instead!
Background
Some chemical reactions happen very fast (think vinegar and baking soda), whereas others take a very long time (such as rust forming on metal). In chemical reactions that include a solid as one of the reactants, you can actually change the reaction rate by varying the size of the solid that reacts with the liquid or the gas. How does this work? For a chemical reaction to happen, the molecules or atoms of the reactants need to collide with each other. This can only happen at the surface of the solid, as all the molecules trapped within the body of the solid cannot react until they meet the molecules of the other reactant. However, if you take the same material and break it into smaller pieces, there is much more surface area exposed that can interact with the other components—allowing the chemical reaction to occur much more quickly.
Explanation:
Explanation:
An increase in temperature typically increases the rate of reaction. An increase in temperature will raise the average kinetic energy of the reactant molecules. Therefore, a greater proportion of molecules will have the minimum energy necessary for an effective collision (Figure.
By decreasing the particle size of a reactant, we are increasing its surface area. The greater the surface area, the higher the chance of collisions, thus the faster the rate of reaction. The smaller the particle size the faster the reaction.
Ann increase in temperature causes an increase in the reaction rate. A higher temperature means that the molecules have a higher average kinetic energy. This produces more collisions per unit time. It also increases the number of collisions that have enough energy to cause a reaction
