what are the controlled, independent and dependent variables in an experiment, where you test and observe the reactions of acids and carbonates?acids: hydrochloric and nitric acid. carbonates...

what are the controlled, independent and dependent variables in an experiment, where you test and observe the reactions of acids and carbonates?

acids: hydrochloric and nitric acid.

carbonates :sodium, lithium, calcium, ammonium and nickel (II) carbonate.

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ndnordic's profile pic

ndnordic | High School Teacher | (Level 2) Associate Educator

Posted on

One type of experiment you could perform would be to compare the reactivity of HCl and HNO3 with the various carbonates you have listed.  You would control the concentration of the acids and of the carbonates so they are the same in every test. You would also want to control the initial temperature of all the solutions so you can measure any changes in temperature in the various reactions. You would also control the rate of addition of the acid solution to the carbonate solution.

The acids would be the independent variables and the carbonates the dependent variables. Thus, the behavior of each carbonate would depend on the type of acid used.

Some of the effects you could observe and/or measure would be:

any changes in color, any formation of a precipitate, any change in temperature, the volume of gas released, change in pH as the reaction proceeds, do all of the carbonates react with both acids?

You could also rank the carbonates in terms of their relative reactivity with each of the acids.

baystation's profile pic

baystation | (Level 1) eNoter

Posted on

Without more information about this experiment, it will be difficult to give you an accurate answer.  

It looks like you are testing both HCl and HNO3 on a variety of carbonates.  There should only be one independent variable in any experiment and the list you gave makes me think there is more than one experiment going on.  

The independent variable is the variable that you control and that changes in the experiment.  Let’s say it’s the quantity of acid.  It could also be the time you allow the acid and carbonate to react or the temperature at which you perform the reaction.  You decide what will be the independent variable when you craft the experiment.  It can be just about anything.  Everything else in the experiment should be a controlled variable. 

If your independent variable is the temperature of the experiment, you may choose a variety of temperatures to conduct the experiment but everything else – the quantity of acid and carbonate, the duration of the reaction, the humidity… will stay the same throughout the experiment.  They are controlled by you!

The dependant variables are typically what you are looking for.  They are the products or effects that happen BECAUSE OF your independent variable.  Going back to our example, let’s say that the amount of CO2 created during our reactions changed when we increased or decreased the temperature.  We could say that the amount of CO2 produced was dependant on the temperature of the reaction and CO2 would be the dependant variable.

Take a look at the link for more info.

Hope this helps!

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