# Reaction Rate

by jackbardsleystudentscotchwaedu (student)

Science Reaction Rate Between an Acid and Metal Investigation

PROBLEM/RESEARCH QUESTION

In this investigation, a controlled experiment will be conducted to determine whether the varying concentration of an acid alters its reaction rate with a metal substance and if so, what is the resultant relationship between the rate of reaction and the concentration of the acid. In particular, we will be reacting Sulfuric acid (H2SO4) with Magnesium metal (Mg) and collect data based on the resultant hydrogen gas produced by the reaction.

Word Equation:

Magnesium + Sulfuric Acid → Hydrogen gas + Magnesium Sulfate

Balanced Equation:

Mg (S)  + H2SO4 (aq) → MgSo4 (aq) + H2 (g)

Research will be formulated by conducting a controlled experiment in which we will react 0.05g of Magnesium metal ribbons (Mg) with 10mL of four different H2SO4 (Sulfuric Acid) solutions varying in concentration and determine the time it takes for the reaction to produce 20mL of Hydrogen gas with each varying concentration.

HYPOTHESIS

I hypothesise that as the concentration of the H2SO4 solution increases/strengthens (measured in molarity mass), it will correspond to an increased/quicker rate of reaction with Mg metal. Hence, I also hypothesise that - based on the above premise- the 2M solution of H2SO4 would be the quickest to produce 20mL of H2 gas when reacted with magnesium, as it is the strongest of the four concentrations being trialed. My hypothesis is based upon the scientific reasoning that a more concentrated solution has more particles of the altering reactant (in this case H2SO4) present in a specific volume/amount of space than those present in a more dilute solution. Hence, at a higher concentration, particles are more likely to collide and react with one another, forming a larger number of new bonds between the two reactants. The “Collision Theory” (which summaries the previous sentences) infers that the rate of reaction is impacted by how often molecules collide with one another. This can be applied to my hypothesis to suggest that with the occurrence of more collisions in the reaction- due to a higher percentage of particles in the more concentrated H2SO4 solutions- it will result in the formation of more bonds and hence, lead to a quicker rate of reaction between two reactants, leading to a quicker production of 20mL of H2 gas.

VARIABLES

The independent variable (the variable being changed): The independent variable is going to be the varying concentration- measured in molarity mass (M)- of Sulfuric acid (H2SO4) solution. Four different concentrations will be trialed- 0.5M, 1.0M, 1.5M and 2.0M- each three times and then averaged out so that we achieve a more accurate result. We will alter this variable by changing the concentration of the H2SO4 solution in order to determine a relationship between the strength of an acid and its rate of reaction with a metal substance (in this case: Magnesium metal). The different concentrations have been prepared in the laboratory before the experiment and hence, we do not have to self-prepare the concentrations in class.

The dependent variable (the variable being measured): The dependent variable is going to be the varying rate of reaction between a magnesium metal ribbon (Mg) and different concentrations of sulfuric acid (H2SO4). In particular, we will measure and record the time taken by the reaction to produce 20 mL of hydrogen gas in an inverted measuring cylinder. This will indicate the rate at which each concentration reacts and allow us to draw conclusions on how altering the concentration affects the rate of reaction between an acid solution and metal substance. We will measure this variable through the application of a stopwatch and gather recordings/data in seconds. The stopwatch will start when 10mL of H2SO4 is poured into the test tube, reacting with the magnesium ribbon, and will stop timing when the volume of water in the inverted measuring cylinder has decreased by 20mL- indicating that it has been replaced with an equivalent amount of hydrogen gas.

The control variables (the variables kept the same): The other variables, which we need to keep constant, are:

• The volume of H2SO4 being added to each reaction. This will be kept constant throughout the investigation by accurately measuring 10mL of H2SO4 solution for each trial in a measuring cylinder. This is vital for a fair test as varying it would mean that reaction rate is not only being altered by the effects of varying concentration but also that of volume.
• The same climatic conditions present around the experiment. The climatic conditions, in particular temperature will remain the same throughout ...