How can reaction rates be measured

This can be measured by the manometer as a function of time. By employing the ideal gas law—the concentration of a gas is proportional to its partial pressure—the rate of a chemical reaction can be calculated. To learn more about our GDPR policies click here. If you want more info regarding data storage, please contact gdpr jove. Your access has now expired. Provide feedback to your librarian. If you have any questions, please do not hesitate to reach out to our customer success team.

Login processing Chapter Chemical Kinetics. Chapter 1: Introduction: Matter and Measurement. Chapter 2: Atoms and Elements. Chapter 3: Molecules, Compounds, and Chemical Equations. Chapter 4: Chemical Quantities and Aqueous Reactions. Chapter 5: Gases. Chapter 6: Thermochemistry. Chapter 7: Electronic Structure of Atoms. Chapter 8: Periodic Properties of the Elements. Chapter 9: Chemical Bonding: Basic Concepts. Chapter Liquids, Solids, and Intermolecular Forces. Chapter Solutions and Colloids.

Chapter Chemical Equilibrium. Chapter Acids and Bases. Chapter Acid-base and Solubility Equilibria. Chapter Thermodynamics. Chapter Electrochemistry. Chapter Radioactivity and Nuclear Chemistry. Chapter Transition Metals and Coordination Complexes. Chapter Biochemistry. Full Table of Contents. This is a sample clip. Sign in or start your free trial. JoVE Core Chemistry. Previous Video Next Video. Next Video Embed Share. Reaction rates can be studied by determining the change in concentrations of reactants or products as a function of time.

Chemistry Chemical Kinetics Rate of Reactions. May 4, See below. Explanation: The reaction rate can be found from either the rate of consumption of a reactant or rate of production of a product. Related questions How do you calculate rate of reaction?

How can rate of reaction be affected? How can rate of reaction be increased? Before performing any stoichiometric calculation, we must first have a balanced chemical equation. Take, for example, the reaction of hydrogen and oxygen gas to form liquid water:. As it is written here, we should notice that our equation is not balanced, because we have two oxygen atoms on the left side of the equation, but only one on the right.

In order to balance this, we need to add a stoichiometric coefficient of 2 in front of liquid water:. In doing this, however, our hydrogens have become unbalanced. To finish balancing the equation, we must add a coefficient of 2 in front of hydrogen gas:.

Keep in mind, however, that in our calculations, we will often be working in moles, rather than in molecules. In our example here, we can see that the stoichiometric coefficient of H 2 g is 2, while for O 2 g it is 1, and for H 2 O l it is 2. Occasionally, you might come across the term stoichiometric number, which is related to the stoichiometric coefficient, but is not the same.

Water is 2, hydrogen gas is 2, and oxygen gas is 1. For reactants, the stoichiometric number is the negative of the stoichiometric coefficient, while for products, the stoichiometric number is simply equal to the stoichiometric coefficient, remaining positive.

Therefore, for our example here, the stoichiometric number for H 2 g is -2, and for O 2 g it is This is because in this reaction, H 2 g and O 2 g are reactants that are consumed, whereas water is a product that is produced. Lastly, you might occasionally come across some chemical species that are present during a reaction, but that are neither consumed nor produced in the reaction.

A catalyst is the most familiar example of this. For such species, their stoichiometric coefficients are always zero.

In our balanced chemical equation, the coefficient for H2 g is 1, and the coefficient for HCl g is 2. The molar ratio between these two compounds is therefore This tells us that for every 1 mole of H2 g that is consumed in the reaction, 2 moles of HCl g are produced. Privacy Policy. Skip to main content. Chemical Kinetics. Search for:. Reaction Rates Measuring Reaction Rates Reaction rates are determined by observing the changes in the concentrations of reactants or products over a specific time frame.

Learning Objectives Produce rate expressions when given chemical reactions and discuss methods for measuring those rates. The rate of reaction can be observed by watching the disappearance of a reactant or the appearance of a product over time.