could anyone help me with these pre lab questions ? CHEM 121 Lab 4: Factors Affe

Question

could anyone help me with these pre lab questions ?

CHEM 121 Lab 4: Factors Affecting Rate of Reactions Objective: mentally observe the factors affecting the rates of reactions. 1. Experi Pre Lab Questions: ed answers submitted at the beginning of lab 3 points) how each 1. Identify 4 factors that affect the rate of reactions. Provide a short explanation of factor affects the rate of a reaction. quantitative for this 2. Rate is quantitative with unit of M/sec. We are not measuring anything 3. lab. How would you study the rate for this can make each reaction to better List 4 observations that you during 4 chemically. understand what is going on Procedures: Investigation 1-Nature of reactants 1 #1 to#5. each, place 1-cm strip of Mg 1. Obtain 5 test tubes and number For 2. Add 1mL of 2M sulfuric acid 3. Add 1mL of 2M hydrochloric acid to #2 4. Add 1 mL of M nitric acid to #3 5. Add 1mL of 2M phosphoric acid to #4

Explanation / Answer

For first prelab question:

Factors affecting reaction rate:

The reaction usually has the following format:

Rate= k * [A]x *[Y]z

Where we can see that, in the first place, the reaction rate is directly proportional to the concentration of reactants. The more the reactants, the faster the rate.

Also, the reaction rate constant has the following expression:

k=AeEa/RT

Where we can see that it is affected directly by the temperature of the reaction. If we increase the temperature, the constant value increases, thus increasing the rate of reaction.

Another factor affecting rate of reaction is surface area and collisions. The higher the surface area, the higher the rate of the reaction.

Lastly, catalysts are a factor that affect rates of reaction. It increases the rate of reaction without affecting the chemical composition of products.

For studying the rate of reaction in a qualitative point of view, you could observe how fast the reactants disappear if visible, such as the magnesium bar of the problem. Also, how vigorous the reaction turns out is another indicator of how fast is the rate of the reaction.

Observations that could be made to study the reactions:

1.- How vigorous the reactions are, gas production.

2.- Changes in color

3.- Consumption or the generation of a single homogenous mixture.

4.- Temperature changes in the system.

5.- If a reaction occurs at all.

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