USING ENGLISH TO PREDICT RENDEMENT OF PRODUCT A REACTION

Chemistry:

Predicting Reaction Products

When cooking, it's frequently handy to predict what will happen when we mix a bunch of ingredients together. For example, if we're interested in making a delicious new salad dressing, we would have a very small chance of making anything edible if we had no way of knowing which ingredients would have the greatest chance of succeeding.

Likewise, it's often necessary for chemists to predict the chemical reactions that will take place when two chemicals are combined. For example, if we're adding a chemical to a tank of toxic waste to stabilize it, we'd be very unhappy if we failed to predict an explosive reaction.

The Mole Says

The tips in this section, while helping you to figure out what reaction might occur, aren't infallible in correctly predicting the reaction that will take place. However, if you're not sure what will happen, these tips will be useful in suggesting some possibilities.

An easy way to predict what reaction will take place when two chemicals are mixed is to identify the type of reaction that's likely to occur when the chemicals are combined. Of course, we mentioned before that these types of reaction are arbitrary, but they do sometimes have a useful purpose.

Bad Reactions

There are two common mistakes when predicting the products of a chemical reaction. The first is predicting the formation of a theoretically impossible product such as NaCO3 or Ag4Cl. The second is failing to balance the equation once the products have been accurately predicted

Here are some tips you may find handy in helping to predict the type of reaction that will occur if you know only the reactants. Keep in mind that not all combiations of chemicals will result in a chemical reaction—these tips are handy only for helping to predict what would happen should they happen to react.

You've Got Problems

Problem 4: Write balanced chemical equations for the reactions that might occur when the following reactants are combined:

 a) NaOH + H2 SO4 ⇔ ?

 b) NH3 + I2 ⇔ ?

 c) C3H8O + O2 ⇔ ?

If two ionic compounds are combined, it's usually safe to predict that a double displacement reaction will occur.

If the chemicals mixed are oxygen and something containing carbon, it's usually a combustion reaction.

If we start with only one reactant, the reaction taking place is probably a decomposition reaction. To predict the products of such a reaction, see what happens if the chemical breaks into smaller, familiar products such as water, carbon dioxide, or any of the gaseous elements.

When pure elements are combined, synthesis reactions are the frequent result.

If a pure element combines with an ionic compound, a single displacement reaction may take place.

If a compound containing the hydroxide ion is involved, check the other compound to see if it contains hydrogen. If it does, it may be an acid-base reaction.

In chemistry, the chemical yield, the yield of the reaction, or only the rendement refers to the amount of reaction product produced in the chemical reaction. Absolute rendement can be written as weight in grams or in moles (molar yield). The relative yield used as a calculation of the effectiveness of the procedure is calculated by dividing the amount of product obtained in moles by the theoretical yield in moles:

To obtain a percentage yield, multiply the fractional yield by 100%.

One or more reactants in chemical reactions are often used redundantly. The theoretical rendement is calculated based on the number of moles of the limiting reagent. For this calculation, it is usually assumed that there is only one reaction involved.

The ideal chemical yield value (theoretical rendement) is 100%, a value highly unlikely to be achieved in its practice. Calculate the percentage of rendement that is by using the following equations percent rendemen = weight yield / weight of yield divided by the sample weight multiplied by 100%