What are the independent and dependent variables when determining the percentage water in hydrated copper sulfate salts, while designing the experiment? The question states 'Select sensible amounts to make the independent variable the limiting reagent and the control in excess.' and the next one states 'Suggest suitably large range of independent variable'.
In this experiment, the independent variable is the factor that you are intentionally changing or manipulating. The dependent variable is the factor that you are measuring or observing as a result of the changes made to the independent variable.
In the case of determining the percentage of water in hydrated copper sulfate salts, the independent variable would be the amount of hydrated copper sulfate used in the experiment. You would vary the amount of the salt to see how it affects the overall percentage of water in the compound. The independent variable is also specified to be the limiting reagent, which means it will be the component that gets entirely consumed in the reaction, thereby limiting the amount of product formed.
The dependent variable, in this case, would be the percentage of water in the hydrated copper sulfate. This is what you would measure or calculate based on the changes made to the independent variable.
To select sensible amounts for the independent variable to be the limiting reagent, you would typically start with a balanced chemical equation for the reaction between hydrated copper sulfate and water. This equation will provide you with the stoichiometry (the mole ratios) needed to calculate the amount required for the limiting reagent.
For example, if the balanced equation is:
CuSO4(XH2O) + YH2O -> CuSO4 + ZH2O,
where CuSO4(XH2O) represents the hydrated form of copper sulfate and CuSO4 represents the anhydrous form, you can determine the stoichiometric ratios between the reactants and products. From these ratios, you can calculate the appropriate amount of hydrated copper sulfate to use as the independent variable.
To suggest a suitable large range for the independent variable, you would want to choose different amounts of hydrated copper sulfate salts that cover a wide range of values. This will allow you to observe the effect of varying amounts on the percentage of water in the compound. For example, you could choose amounts ranging from 1 gram to 10 grams of hydrated copper sulfate.
Remember to conduct multiple trials for each amount tested to ensure accuracy and reliability of your results.